Eaton Vance National Municipal Opportunities Trust posts 4.41% NAV return | EOT SEC Filing

Eaton Vance

National Municipal Opportunities Trust (EOT)

Annual Report

March 31, 2026

Commodity Futures Trading Commission Registration. The Commodity Futures Trading Commission (“CFTC”) has adopted regulations that subject registered investment companies and advisers to regulation by the CFTC if a fund invests more than a
prescribed level of its assets in certain CFTC-regulated instruments (including futures, certain options and swap agreements) or markets itself as providing investment exposure to such instruments. The investment adviser has claimed an exclusion
from the definition of “commodity pool operator” under the Commodity Exchange Act with respect to its management of the Fund. Accordingly, neither the Fund nor the adviser with respect to the operation of the Fund is subject to CFTC
regulation. Because of its management of other strategies, the Fund’s adviser is registered with the CFTC as a commodity pool operator. The adviser is also registered as a commodity trading advisor.

Fund shares are not insured by the FDIC and are not deposits or
other obligations of, or guaranteed by, any depository institution. Shares are subject to investment risks, including possible loss of principal invested.

Annual Report March 31, 2026

Eaton Vance

National Municipal Opportunities Trust

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Management’s Discussion of Fund Performance^†

Economic and Market Conditions

Municipal bonds declined early in the 12-month period beginning
April 1, 2025, as optimism following the first Federal Reserve rate cut in 2024 faded and volatility took hold. Economic uncertainty, tax policy debates and negative seasonal technicals drove yields higher across high-grade municipals. April brought
exceptional turbulence after President Trump’s Liberation Day trade policy announcement introduced global growth uncertainty. On April 9 and 10, the municipal market recorded its two largest single-day index moves in opposite directions, as
measured by the Bloomberg Municipal Bond Index (the Index): -2% followed by +2.9%.

From May through July, persistent macro headwinds restrained
fixed-income performance. President Trump’s “One Big Beautiful Bill” drove long-end rates higher as markets questioned the impact of an additional $2.4 trillion in projected deficits over the next decade. Combined with ongoing
tariff uncertainty, the policy outlook shifted from expected rate cuts to a wait-and-see stance.

In September, the market strengthened as renewed Federal
Reserve easing and supportive technicals drove yields lower. Despite supply being 30% above the five-year average, reinvestment flows and inflows into municipal funds supported a 2.32% gain for the month. Treasury yields also declined on signs of
labor market cooling, but municipals outperformed as yield curve dynamics favored tax-exempt securities. Municipals rallied further with the municipal market posting strong gains in October as well, marking the best October performance since 1995 as
the Index advanced 1.24%. Both Treasury and municipal curves flattened over the two-month period, with the spread between the two-year and 30-year maturities (commonly referred to as the 2s30s spread) ending at +169 basis points (bps) for municipals
versus +107 bps for Treasuries.

The municipal market
delivered muted performance in November and December following October’s strong rally. Full-year 2025 gross issuance reached a record $565 billion, surpassing the prior 2020 peak, driven by $517 billion of tax-exempt issuance. Market
performance for the month was governed by curve dynamics, as short-term yields declined while the 30-year yields rose by eight bps.

In January and February municipal markets benefited from a
strong technical backdrop and robust investor demand. New issuance was down 7% year over year in January, and fund flows approached $13 billion for the month, the strongest January since 1992. Fund flows remained strong in February and were
positive, bringing the two-month total to $17.60 billion. At the end of February, municipals were off to a strong start for the year, the Index returned 2.2% year to date, led by the 17-to-22-year segment.

Market tone shifted at the start of March following the
February 28 joint US and Israeli strikes on Iran, which lifted oil prices and renewed inflation concerns. March pressured the municipal market with record issuance and a sharp backup in rates, leading to broad negative performance. Within the Index,
returns declined -2.32% for the month, erasing year-to-date gains and leaving performance at -0.18%. The selloff was driven by a significant rise in yields, with AAA municipal rates increasing 39 bps in five years, 60 bps in 10 years and 29 bps in
30 years as the belly of the curve underperformed.

For
the full period, the Index returned 4.29%. Performance was led by the short end of the curve, where yields declined and prices rose for bonds maturing within 10 years. In contrast, longer maturities (20- to 30-years) underperformed as yields rose
and prices fell. During a period with investor demand concentrated in short-duration and higher-quality credits, lower-quality municipal bonds underperformed, with the Bloomberg High Yield Municipal Bond Index returning just 2.35%.

Fund Performance

For the 12-month period ended March 31, 2026, Eaton Vance
National Municipal Opportunities Trust (the Fund) returned 4.41% at net asset value (NAV) of its common shares, outperforming its benchmark, the Bloomberg Municipal Bond Index (the Index), which returned 4.29% during the period.

The Fund’s primary investment objective is to provide
current income exempt from federal income tax. Capital appreciation is a secondary objective.

During normal market conditions, the Fund will invest at least
80% of its gross assets in debt obligations issued by or on behalf of states, territories, and possessions of the U.S., including the District of Columbia, and their political subdivisions, agencies, or instrumentalities, the interest on which is
exempt from regular federal income tax (“municipal obligations”), including investments in residual interest bonds whose interest is exempt from regular federal income tax. During normal market conditions, at least 70% of the
Fund’s investments in municipal obligations will be rated investment-grade quality — Baa/BBB or higher by Moody’s, S&P, or Fitch — at the time of investment.

The Fund’s managers may employ leverage through tender
option bond (TOB) financing to seek to enhance tax-exempt income potential. The use of leverage has the effect of achieving additional exposure to the municipal bond market, magnifying the Fund’s exposure to its underlying investments in both
up and down markets.

See Endnotes and Additional Disclosures in this report.

Past performance is no guarantee of future results.
Returns are historical and are calculated net of management fees and other expenses by determining the percentage change in net asset value (NAV) or market price (as applicable) with all distributions reinvested in accordance with the Fund’s
Dividend Reinvestment Plan. Furthermore, returns do not reflect the deduction of taxes that shareholders may have to pay on Fund distributions or upon the sale of Fund shares. Performance at market price will differ from performance at NAV due to
variations in the Fund’s market price versus NAV, which may reflect factors such as fluctuations in supply and demand for Fund shares, changes in Fund distributions, shifting market expectations for the Fund’s future returns and
distribution rates, and other considerations affecting the trading prices of closed-end funds. Investment return and principal value will fluctuate so that shares, when sold, may be worth more or less than their original cost. Performance for
periods less than or equal to one year is cumulative. Performance is for the stated time period only; due to market volatility, current Fund performance may be lower or higher than the quoted return. For performance as of the most recent month-end,
please refer to eatonvance.com.

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Management’s
Discussion of Fund Performance^† — continued

Contributors to Fund performance versus the Index during the
period included the Fund’s use of TOB leverage, which supported results in a favorable municipal bond environment. Allocations to municipal taxable securities also contributed positively. In addition, security selection within the hospital
sector enhanced relative performance during the period.

In contrast, detractors from Fund performance versus the Index
during the period included security selection within AAA rated bonds. An overweight exposure to long-bond maturities (22+ years) also weighed on relative performance, as did security selection among bonds with 4.00% coupon structures.

See Endnotes and
Additional Disclosures in this report.

Past performance is no guarantee of future results.
Returns are historical and are calculated net of management fees and other expenses by determining the percentage change in net asset value (NAV) or market price (as applicable) with all distributions reinvested in accordance with the Fund’s
Dividend Reinvestment Plan. Furthermore, returns do not reflect the deduction of taxes that shareholders may have to pay on Fund distributions or upon the sale of Fund shares. Performance at market price will differ from performance at NAV due to
variations in the Fund’s market price versus NAV, which may reflect factors such as fluctuations in supply and demand for Fund shares, changes in Fund distributions, shifting market expectations for the Fund’s future returns and
distribution rates, and other considerations affecting the trading prices of closed-end funds. Investment return and principal value will fluctuate so that shares, when sold, may be worth more or less than their original cost. Performance for
periods less than or equal to one year is cumulative. Performance is for the stated time period only; due to market volatility, current Fund performance may be lower or higher than the quoted return. For performance as of the most recent month-end,
please refer to eatonvance.com.

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Performance

Portfolio Manager(s) Cynthia J.
Clemson and William J. Delahunty, Jr., CFA

Growth of $10,000

This graph shows the change in value of a hypothetical
investment of $10,000 in the Fund for the period indicated. For comparison, the same investment is shown in the indicated index.

See Endnotes and Additional Disclosures in this report.

Past performance is no guarantee of future results.
Returns are historical and are calculated net of management fees and other expenses by determining the percentage change in net asset value (NAV) or market price (as applicable) with all distributions reinvested in accordance with the Fund’s
Dividend Reinvestment Plan. Furthermore, returns do not reflect the deduction of taxes that shareholders may have to pay on Fund distributions or upon the sale of Fund shares. Performance at market price will differ from performance at NAV due to
variations in the Fund’s market price versus NAV, which may reflect factors such as fluctuations in supply and demand for Fund shares, changes in Fund distributions, shifting market expectations for the Fund’s future returns and
distribution rates, and other considerations affecting the trading prices of closed-end funds. Investment return and principal value will fluctuate so that shares, when sold, may be worth more or less than their original cost. Performance for
periods less than or equal to one year is cumulative. Performance is for the stated time period only; due to market volatility, current Fund performance may be lower or higher than the quoted return. For performance as of the most recent month-end,
please refer to eatonvance.com.

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Footnotes:

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

The Fund’s Investment
Objectives, Principal Strategies and Principal Risks^‡

Investment Objectives. The
Fund’s primary investment objective is to provide current income exempt from federal income tax. Capital appreciation is a secondary objective.

Principal Strategies.  During
normal market conditions, the Fund will invest at least 80% of its gross assets in debt obligations issued by or on behalf of states, territories and possessions of the United States, including the District of Columbia, and their political
subdivisions, agencies or instrumentalities, the interest on which is exempt from regular federal income tax (“municipal obligations”). For purposes of this 80% policy, municipal obligations will include investments in residual interest
bonds whose interest is exempt from regular federal income tax.

During normal market conditions, at least 70% of the
Fund’s investments in municipal obligations will be investment grade quality at time of investment. A municipal obligation is considered investment grade quality if it is either (i) rated within the four highest ratings categories by at least
one nationally recognized statistical rating organization (a “Rating Agency”), which are those rated Baa or higher by Moody’s Investors Service, Inc. (“Moody’s”) or BBB or higher by Standard & Poor’s
Ratings Services (“S&P”) or Fitch Ratings (“Fitch”), or (ii) an unrated municipal obligation that the Fund’s investment adviser considers to be of investment grade quality. If a municipal obligation is rated
differently by two or more Rating Agencies, the Fund will use the higher of such ratings (the “Municipal Obligation Rating”). If a municipal obligation is insured, the Fund will use the higher of the Municipal Obligation Rating or the
insurance issuer’s rating. Securities rated in the fourth highest category (i.e., Baa by Moody’s or BBB by S&P or Fitch) are considered investment grade quality, but may have speculative characteristics.

Up to 30% of the Fund’s investments in municipal
obligations may be below investment grade quality at time of investment. A municipal obligation is considered below investment grade quality if it is either (i) rated below investment grade by a Rating Agency, or (ii) an unrated municipal obligation
that the Fund’s investment adviser considers to be of comparable quality. Municipal obligations of below investment grade quality (commonly referred to as “junk” bonds) involve special risks as compared to municipal obligations of
investment grade quality. These risks include greater sensitivity to a general economic downturn, greater market price volatility and less secondary market trading. The Fund may invest in below investment grade municipal obligations of any quality.
This means that the Fund’s investments in municipal obligations may include securities of issuers that are having financial difficulties, which may include being in default on obligations to pay principal or interest thereon when due or
involved in bankruptcy or insolvency proceedings (such securities are commonly referred to as “distressed securities”). While the Fund is not limited in its exposure to any issuer or obligor, the Fund generally will not invest more than
2% of its gross assets in any single security of below investment grade quality. Under normal market conditions, the Fund will seek to maintain an average credit quality of investment grade.

Up to 20% of the Fund’s investments in municipal
obligations may be subject to the alternative minimum tax. Up to 5% of the Fund’s investments in municipal obligations may be collateralized by the proceeds from class action or other litigation against the tobacco industry. Such municipal
obligations are backed solely by expected revenues to be derived from lawsuits involving tobacco-related deaths and illnesses which were settled between certain states and American tobacco companies. The Fund invests in residual interest bonds, also
known as inverse floating rate securities, which have the economic effect of leverage. If the Fund invests 25% or more of its gross assets in any one state (or U.S. territory) the Fund may be more susceptible to adverse economic, political or
regulatory occurrences affecting a particular state (or territory).

The Fund may purchase municipal obligations in the form of
bonds, notes, leases or certificates of participation; structured as callable or non-callable; with payment forms that include fixed coupon, variable rate, zero-coupon, capital appreciation bonds, residual interest bonds and short-term floating-rate
securities. Such municipal obligations may be acquired through investments in pooled vehicles, partnerships, or other investment companies. No established resale market exists for certain of the municipal obligations in which the Fund may invest.
The Fund has no limitation on the amount of its assets that may be invested in securities that are not readily marketable or are subject to restrictions on resale.

In addition to investing in residual interest bonds, the Fund
may invest without limitation in other derivative instruments (which are instruments that derive their value from another instrument, security or index) acquired for hedging purposes. The Fund may purchase and sell various kinds of financial futures
contracts and related options, including futures contracts and related options based on various debt securities and securities indices. The Fund also may enter into interest rate, total return and other swaps and forward rate contracts to seek to
hedge against changes in interest rates or for other risk management purposes.

During unusual market conditions, the Fund may invest up to
100% of its assets in cash or cash equivalents temporarily, which may be inconsistent with its investment objective(s) and other policies.

Principal Risks

Market Discount Risk. As with
any security, the market value of the Fund’s common shares may increase or decrease from the amount initially paid for the common shares. The Fund’s common shares have traded both at a premium and at a discount relative to NAV. The
shares of closed-end management investment companies frequently trade at a discount from their NAV. This is a risk separate and distinct from the risk that the Fund’s NAV may decrease.

Investment and Market Risk. An
investment in the Fund’s common shares is subject to investment risk, including the possible loss of the entire principal amount invested. An investment in common shares represents an indirect investment in the securities owned by the Fund,
which will generally trade in the over-the-counter (“OTC”) markets. The common shares at any point in time may be worth less than the original investment, even after taking into account any reinvestment of distributions.

See Endnotes
and Additional Disclosures in this report.

6

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

The Fund’s Investment
Objectives, Principal Strategies and Principal Risks^‡ — continued

The value of investments held by the Fund may increase or
decrease in response to social, economic, political, financial, public health crises or other disruptive events (whether real, expected or perceived) in the U.S. and global markets and include events such as war, natural disasters, epidemics and
pandemics, terrorism, conflicts and social unrest. These events may negatively impact broad segments of businesses and populations and may exacerbate pre-existing risks to the Fund. The frequency and magnitude of resulting changes in the value of
the Fund’s investments cannot be predicted. Certain securities and other investments held by the Fund may experience increased volatility, illiquidity, or other potentially adverse effects in reaction to changing market conditions. Monetary
and/or fiscal actions taken by U.S. or foreign governments to stimulate or stabilize the global economy may not be effective and could lead to high market volatility. No active trading market may exist for certain investments held by the Fund, which
may impair the ability of the Fund to sell or to realize the current valuation of such investments in the event of the need to liquidate such assets.

Municipal Obligations Risk.
Because the Fund may invest in municipal obligations, the Fund may be susceptible to political, legislative, economic, regulatory, tax or other factors affecting issuers of these municipal obligations, such as state and local governments and their
agencies. To the extent that the Fund invests in municipal obligations of issuers in the same state, U.S. territory, or economic sector, it could be more sensitive to economic, business or political developments that affect such state or sector.
Municipal obligations and their issuers may be more susceptible to downgrade, loss of revenue, default and bankruptcy during periods of economic stress. The amount of public information available about municipal obligations is generally less than
for corporate equities or bonds, meaning that the investment performance of municipal obligations may be more dependent on the analytical abilities of the investment adviser than stock or corporate bond investments. The secondary market for
municipal obligations also tends to be less well-developed and less liquid than many other securities markets, which may limit the Fund’s ability to sell its municipal obligations at attractive prices. The differences between the price at
which an obligation can be purchased and the price at which it can be sold may widen during periods of market distress. Less liquid obligations can become more difficult to value and be subject to erratic price movements.

Interest Rate Risk. In general,
the value of income securities will fluctuate based on changes in interest rates. The value of these securities is likely to increase when interest rates fall and decline when interest rates rise. Duration measures the time-weighted expected cash
flows of a fixed-income security, while maturity refers to the amount of time until a fixed-income security matures. Generally, securities with longer durations or maturities are more sensitive to changes in interest rates than securities with
shorter durations or maturities, causing them to be more volatile. Conversely, fixed-income securities with shorter durations or maturities will be less volatile but may provide lower returns than fixed-income securities with longer durations or
maturities. Because the Fund is managed toward an income objective, it may hold more longer-duration or maturity obligations and thereby be more exposed to interest rate risk than municipal income funds that are managed with a greater emphasis on
total return. The impact of interest rate changes is significantly less for floating-rate instruments that have relatively short periodic rate resets (e.g., ninety days or less). In a rising interest rate environment, the durations or effective
maturities of income securities that have the ability to be prepaid or called by the issuer may be extended. In a declining interest rate environment, the proceeds from prepaid or maturing instruments may have to be reinvested at a lower interest
rate.

Credit Risk.
Investments in municipal obligations and other debt obligations (referred to below as “debt instruments”) are subject to the risk of non-payment of scheduled principal and interest. Changes in economic conditions or other circumstances
may reduce the capacity of the party obligated to make principal and interest payments on such instruments and may lead to defaults. Such non-payments and defaults may reduce the value of Fund shares and income distributions. The value of debt
instruments also may decline because of concerns about the issuer’s ability to make principal and interest payments. In addition, the credit ratings of debt instruments may be lowered if the financial condition of the party obligated to make
payments with respect to such instruments deteriorates. In order to enforce its rights in the event of a default, bankruptcy or similar situation, the Fund may be required to retain legal or similar counsel, which may increase the Fund’s
operating expenses and adversely affect net asset value. Municipal obligations may be insured as to principal and interest payments. If the claims-paying ability or other rating of the insurer is downgraded by a rating agency, the value of such
obligations may be negatively affected.

Lower Rated
Investments Risk. Investments rated below investment grade and comparable unrated investments (sometimes referred to as “junk”) are speculative because of increased credit risk relative to other fixed
income investments. Changes in economic conditions or other circumstances typically have a greater effect on the ability of issuers of lower rated investments to make principal and interest payments than they do on issuers of higher rated
investments. An economic downturn generally leads to a higher non-payment rate, and a lower rated investment may lose significant value before a default occurs. Lower rated investments typically are subject to greater price volatility and
illiquidity than higher rated investments.

Inflation
Risk/Deflation Risk. Inflation risk is the risk that the value of assets or income from investment will be worth less in the future as inflation decreases the value of money. As inflation increases, the real value
of the common shares and distributions thereon can decline. In addition, during periods of rising inflation, short-term interest rates and the Fund’s cost of leverage would likely increase, reducing returns to the common shareholders to the
extent that such increased cost is not offset by commensurately higher income. Deflation risk is the risk that prices throughout the economy decline over time − the opposite of inflation. Deflation may have an adverse affect on the
creditworthiness of issuers and may make issuer defaults more likely, which may result in a decline in the value of the Fund’s investments.

Unrated Securities Risk. The
Fund may invest in unrated obligations for which Eaton Vance will make a credit quality determination for purposes of the Fund’s credit quality policy. To the extent that the Fund invests in such unrated obligations, the Fund’s credit
quality will be more dependent on Eaton Vance’s credit analysis than if the Fund invested in only rated obligations. Some unrated securities may not have an active trading market or may be difficult to value.

See Endnotes and
Additional Disclosures in this report.

7

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

The Fund’s Investment
Objectives, Principal Strategies and Principal Risks^‡ — continued

Leverage Risk. Certain Fund
transactions may give rise to leverage. Leverage can result from a non-cash exposure to an asset, index, rate or underlying reference instrument. Leverage can also result from borrowings, issuance of preferred shares, or participation in residual
interest bond transactions. Leverage can increase both the risk and return potential of the Fund. The use of leverage may cause the Fund to maintain liquid assets or liquidate portfolio positions when it may not be advantageous to do so to satisfy
its obligations. Leverage may cause the Fund’s NAV to be more volatile than if it had not been leveraged, as certain types of leverage may exaggerate the effect of any increase or decrease in the value of the Fund’s portfolio securities.
The loss on leveraged investments may substantially exceed the initial investment. The Fund intends to use leverage to provide the holders of common shares with a potentially higher return. To the extent the income from the securities purchased with
funds received from leverage exceeds the cost of leverage, the Fund’s returns will be greater than if leverage had not been used. Conversely, if the income from the securities purchased with such funds is not sufficient to cover the cost of
leverage, the return to the Fund will be less than if leverage had not been used, and therefore the amount available for distribution to the Fund’s common shareholders as dividends and other distributions will be reduced. In the latter case,
the investment adviser in its best judgment may nevertheless determine to maintain the Fund’s leveraged position if it deems such action to be appropriate. The use of leverage through participation in residual bond transactions by the Fund
creates an opportunity for increased net income, but, at the same time, creates special risks. The Fund may not be able to adjust its use of leverage rapidly enough to respond to interest rate volatility, inflation, and other changing market
conditions. In particular, reducing and increasing leverage obtained through residual interest bonds is a time intensive process and it is not practicable to rapidly adjust such leverage in response to short-term fluctuations. As a result, the
Fund’s use of leverage may have a negative impact on the Fund’s performance from time to time. There can be no assurance that a leveraging strategy will be successful during any period in which it is employed.

Risk of Residual Interest
Bonds. The Fund may enter into residual interest bond transactions, which expose the Fund to leverage (as discussed above under “Leverage Risk”) and greater risk than an investment in a fixed-rate
municipal bond, including the risk of loss of principal. The interest payments that the Fund receives on the residual interest bonds acquired in such transactions vary inversely with short-term interest rates, normally decreasing when short-term
rates increase. As such, residual interest bonds tend to underperform the market for fixed rate bonds in rising long-term interest rate environments. The value and income of, and market for, residual interest bonds are volatile, and such bonds may
have limited liquidity. As required by applicable accounting standards, the Fund records interest expense as a liability with respect to floating-rate notes and also records offsetting interest income in an amount equal to this expense.

Call and Reinvestment Risks. If
interest rates fall, it is possible that issuers of callable bonds with high interest coupons will “call” (or prepay) their bonds before their maturity date. If a call were exercised by the issuer during a period of declining interest
rates, the Fund would likely replace such called security with a lower yielding security. If that were to happen, it could decrease the Fund’s dividends and possibly could affect the market price of common shares. Similar risks exist when the
Fund invests the proceeds from matured or traded municipal obligations at market interest rates that are below the Fund’s current earnings rate.

Municipal Lease Obligations (“MLOs”) and Certificates
of Participation. The Fund may invest in MLOs and certificates of participation involve special risks not normally associated with general obligations or revenue bonds. MLOs are bonds that are secured by lease
payments made by the party, typically a state or municipality, leasing the facilities (e.g., schools or office buildings) that were financed by the bond. Interest income from MLOs is generally exempt from local and state taxes in the state of
issuance. MLOs, like other municipal debt obligations, are subject to the risk of non-payment. Although MLOs do not constitute general obligations of the issuer for which the issuer’s unlimited taxing power is pledged, the leasing state or
municipality may be obligated to appropriate funds from its general tax revenues to make lease payments as long as it utilizes the leased property. Other lease payments may be subject to annual appropriation or may be made only from revenues
associated with the facility financed. For example, certain lease obligations contain “non-appropriation” clauses, which provide that the issuer has no obligation to make lease or installment purchase payments in future years unless
money is appropriated for such purpose on a yearly basis, which function to render constitutional and statutory requirements for the issuance of debt inapplicable to such obligations. In addition, such leases or contracts may be subject to temporary
abatement of payments in the event the governmental issuer is prevented from maintaining occupancy of the leased premises or utilizing the leased equipment. Although “non-appropriation” lease obligations may be secured by the leased
property, disposition of the property in the event of foreclosure might prove difficult, time consuming and costly, and may result in a delay in recovering or the failure to fully recover ownership of the assets.

A certificate of participation (also referred to as a
“participation”) in a municipal lease is an instrument evidencing a pro rata share in a specific pledged revenue stream, usually lease payments by the issuer that are typically subject to annual appropriation. The certificate generally
entitles the holder to receive a share, or participation, in the payments from a particular project. Certificates of participation involve the same risks as the underlying municipal leases. In addition, the Fund may be dependent upon the municipal
authority issuing the certificate of participation to exercise remedies with respect to an underlying lease. Certificates of participation also entail a risk of default or bankruptcy, both of the issuer of the municipal lease and also the municipal
agency issuing the certificate of participation.

MLOs and
participations therein represent a type of financing that may not have the depth of marketability associated with more conventional securities and, as such, they may be less liquid than conventional securities. Certain MLOs may be deemed illiquid,
unless determined by the Fund’s investment adviser, pursuant to guidelines adopted by the Board, to be liquid securities. The Fund’s investment adviser will consider the factors it believes are relevant to the marketability of the
obligation, to the extent that information regarding such factor is available to the Fund’s investment adviser and pertinent to the liquidity determination, which may include: (1) the willingness of dealers to bid for the obligation; (2) the
number of dealers willing to purchase or sell the obligation and the number of other potential buyers; (3) the frequency of trades and quotes for the obligation; (4) the nature of the marketplace trades, including the time needed to dispose of the
obligation, the method of soliciting offers, and the mechanics of transfer; (5) the willingness of the governmental issuer to continue to appropriate funds for the payment of the obligation; (6) how likely or remote an event of non-appropriation may
be,

See Endnotes and Additional Disclosures in this report.

8

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

The Fund’s Investment
Objectives, Principal Strategies and Principal Risks^‡ — continued

which depends in varying degrees on a variety of factors, including those
relating to the general creditworthiness of the governmental issuer, its dependence on its continuing access to the credit markets, and the importance to the issuer of the equipment, property or facility covered by the lease or contract; (7) an
assessment of the likelihood that the lease may or may not be cancelled; and (8) other factors and information unique to the obligation in determining its liquidity.

The ability of issuers of MLOs to make timely lease payments
may be adversely impacted in general economic downturns and as relative governmental cost burdens are allocated and reallocated among federal, state and local governmental units. Such non-payment would result in a reduction of income from and value
of the obligation. Issuers of MLOs might seek protection under the bankruptcy laws. In the event of bankruptcy of such an issuer, holders of MLOs could experience delays and limitations with respect to the collection of principal and interest on
such MLOs and may not, in all circumstances, be able to collect all principal and interest to which it is entitled. To enforce its rights in the event of a default in lease payments, the Fund might take possession of and manage the assets securing
the issuer’s obligations on such securities or otherwise incur costs to protect its right, which may increase the Fund’s operating expenses and adversely affect the net asset value of the Fund. When the lease contains a non-appropriation
clause, however, the failure to pay would not be a default and the Fund would not have the right to take possession of the assets. Any income derived from the Fund’s ownership or operation of such assets may not be tax-exempt.

Restricted Securities Risk.
Unless registered for sale to the public under applicable federal securities law, restricted securities can be sold only in private transactions to qualified purchasers pursuant to an exemption from registration.
The sale price realized from a private transaction could be less than the Fund’s purchase price for the restricted security. It may be difficult to identify a qualified purchaser for a restricted security held by the Fund and such security
could be deemed illiquid. It may also be more difficult to value such securities.

Derivatives Risk. The
Fund’s exposure to derivatives involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other investments. The use of derivatives can lead to losses because of adverse movements in
the price or value of the security, instrument, index, currency, commodity, economic indicator or event underlying a derivative (“reference instrument”), due to failure of a counterparty or due to tax or regulatory constraints.
Derivatives may create leverage in the Fund, which represents a non-cash exposure to the underlying reference instrument. Leverage can increase both the risk and return potential of the Fund. Derivatives risk may be more significant when derivatives
are used to enhance return or as a substitute for a cash investment position, rather than solely to hedge the risk of a position held by the Fund. Use of derivatives involves the exercise of specialized skill and judgment, and a transaction may be
unsuccessful in whole or in part because of market behavior or unexpected events. Changes in the value of a derivative (including one used for hedging) may not correlate perfectly with the underlying reference instrument. Derivative instruments
traded in OTC markets may be difficult to value, may be illiquid, and may be subject to wide swings in valuation caused by changes in the value of the underlying reference instrument. If a derivative’s counterparty is unable to honor its
commitments, the value of Fund shares may decline and the Fund could experience delays in (or be unable to achieve) the return of collateral or other assets held by the counterparty. The loss on derivative transactions may substantially exceed the
initial investment. A derivative investment also involves the risks relating to the reference instrument underlying the investment.

Counterparty Risk. Changes in
the credit quality of the companies that serve as the Fund’s counterparties with respect to its derivatives positions and liquidity providers for the Fund’s residual interest bonds or other investments supported by another party’s
credit will affect the value of those instruments. Certain entities that have served as counterparties in the municipals markets have recently incurred significant financial hardships, including bankruptcy and material loss of credit standing as a
result of exposure to investments that have experienced defaults or otherwise suffered extreme credit deterioration. As a result, such hardships have reduced these entities’ capital and called into question their continued ability to perform
their obligations. By using derivatives or other instruments that expose the Fund to counterparties, the Fund assumes the risk that its counterparties could experience future financial hardship.

The counterparty risk for cleared derivatives is generally
lower than for uncleared OTC derivative transactions since generally a clearing organization becomes substituted for each counterparty to a cleared derivative contract and, in effect, guarantees the parties’ performance under the contract as
each party to a trade looks only to the clearing organization for performance of financial obligations under the derivative contract. However, there can be no assurance that a clearing organization, or its members, will satisfy its obligations to
the Fund.

Liquidity Risk.
The Fund is exposed to liquidity risk when trading volume, lack of a market maker or trading partner, large position size, market conditions, or legal restrictions impair its ability to sell particular investments or to sell them at advantageous
market prices. Consequently, the Fund may have to accept a lower price to sell an investment or continue to hold it or keep the position open, sell other investments to raise cash or abandon an investment opportunity, any of which could have a
negative effect on the Fund’s performance. These effects may be exacerbated during times of financial or political stress.

Insurance Risk. Municipal
obligations may be insured as to their scheduled payment of principal and interest. Although the insurance feature may reduce some financial risks, the premiums for insurance and the higher market price sometimes paid for insured obligations may
reduce the current yield on the insured obligation. Insured obligations also may be secured by bank credit agreements or escrow accounts. Changes in the ratings of an insurer may affect the value of an insured obligation, and in some cases may even
cause the value of a security to be less than a comparable uninsured obligation. The insurance does not guarantee the market value of the insured obligation or the net asset value of the Fund’s shares. The credit rating of an insured
obligation reflects the credit rating of the insurer, based on its claims-paying ability. The obligation of a municipal bond insurance company to pay a claim extends over the life of each insured obligation. Although defaults on insured municipal
obligations have been low to date and municipal bond insurers have met their claims, there is no assurance this will continue. A higher than expected default rate could strain the insurer’s loss reserves and adversely

See Endnotes and
Additional Disclosures in this report.

9

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

The Fund’s Investment
Objectives, Principal Strategies and Principal Risks^‡ — continued

affect its ability to pay claims to bondholders. Because a significant portion
of insured municipal obligations that have been issued and are outstanding is insured by a small number of insurance companies, an event involving one or more of these insurance companies, such as a credit rating downgrade, could have a significant
adverse effect on the value of the municipal obligations insured by that insurance company and on the municipal bond markets as a whole.

Current Regulatory Environment Risk. From time to time proposals have been introduced before Congress for the purpose of restricting or eliminating the federal income tax exemption for interest on certain types of municipal obligations, and it can be
expected that similar proposals may be introduced in the future. Any proposed or actual changes in such rates or exempt status, therefore, can significantly affect the demand for and supply, liquidity and marketability of municipal obligations. This
could in turn affect the Fund’s net asset value and ability to acquire and dispose of municipal obligations at desirable yield and price levels. Legislation may be enacted that could negatively affect the assets of the Fund. Legislation or
regulation may change the way in which the Fund itself is regulated. The Fund’s investment adviser cannot predict the effects of any new governmental regulation that may be implemented, and there can be no assurance that any new governmental
regulation will not adversely affect the Fund’s ability to achieve its investment objective.

State Specific Risk. If the
Fund focuses its investments in any one state (or U.S. territory), the Fund may be more susceptible to adverse economic, political or regulatory occurrences affecting a particular state (or territory). Certain municipal bond issuers in Puerto Rico
have recently experienced financial difficulties and rating agency downgrades, and two such issuers have defaulted on their payment obligations.

Up to 5% of the Fund’s investments in municipal
obligations may be collateralized by the proceeds from class action or other litigation against the tobacco industry. Such municipal obligations are backed solely by expected revenues to be derived from lawsuits involving tobacco-related deaths and
illnesses which were settled between certain states and American tobacco companies. Tobacco settlement bonds are secured by an issuing state’s proportionate share in the Master Settlement Agreement (“MSA”). The MSA is an agreement,
reached out of court in November 1998 between 46 states and nearly all of the major U.S. tobacco manufacturers. Under the terms of the MSA, the actual amount of future settlement payments by tobacco manufacturers is dependent on many factors,
including, but not limited to, annual domestic cigarette shipments, reduced cigarette consumption, increased taxes on cigarettes, inflation, financial capability of tobacco companies, continuing litigation and the possibility of tobacco manufacturer
bankruptcy. Payments made by tobacco manufacturers could be negatively impacted if the decrease in tobacco consumption is significantly greater than the forecasted decline.

Sector and Geographic Risk.
Because the Fund may invest a significant portion of its assets in obligations issued in one or more states and/or U.S. territories and in certain types of municipal or other obligations and/or in certain sectors, the value of Fund shares may be
affected by events that adversely affect a state, U.S. territory, sector or type of obligation and may fluctuate more than that of a fund that invests more broadly. General obligation bonds issued by municipalities can be adversely affected by
economic downturns and any resulting decline in tax revenues.

Recent Market Conditions. Both
U.S. and international markets have experienced significant volatility in recent months and years. As a result of such volatility, investment returns may fluctuate significantly. National economies are substantially interconnected, as are global
financial markets, which creates the possibility that conditions in one country or region might adversely impact issuers in a different country or region. However, the interconnectedness of economies and/or markets may be diminishing, which may
impact such economies and markets in ways that cannot be foreseen at this time.

The U.S. government and the U.S. Federal Reserve, as well as
certain foreign governments and central banks, have from time to time taken steps to support financial markets. The U.S. government and the U.S. Federal Reserve may, conversely, reduce market support activities, including by taking action intended
to increase certain interest rates. This and other government intervention may not work as intended, particularly if the efforts are perceived by investors as being unlikely to achieve the desired results. Changes in government activities in this
regard, such as changes in interest rate policy, can negatively affect financial markets generally, increase market volatility and reduce the value and liquidity of securities in which the Fund invests.

Some countries, including the United States, have adopted more
protectionist trade policies. Slowing global economic growth, the rise in protectionist trade policies, changes to some major international trade agreements, risks associated with the trade agreement between the United Kingdom and the European
Union, and the risks associated with trade negotiations between the United States and China, could affect the economies of many nations in ways that cannot necessarily be foreseen at the present time. In addition, the current strength of the U.S.
dollar may decrease foreign demand for U.S. assets, which could have a negative impact on certain issuers and/or industries.

Regulators in the United States have proposed and adopted a
number of changes to regulations involving the markets and issuers, some of which apply to the Fund. The full effect of various newly adopted regulations is not currently known. Additionally, it is not currently known whether any of the proposed
regulations will be adopted. However, due to the scope of regulations being proposed and adopted, certain of these changes to regulation could limit the Fund’s ability to pursue its investment strategies or make certain investments, may make
it more costly for it to operate, or adversely impact performance.

Tensions, war, or open conflict between nations, such as
between Russia and Ukraine, in the Middle East, or in eastern Asia could affect the economies of many nations, including the United States. The duration of ongoing hostilities and any sanctions and related events cannot be predicted. Those events
present material uncertainty and risk with respect to markets globally and the performance of the Fund and its investments or operations could be negatively impacted.

See Endnotes and Additional Disclosures in this report.

10

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

The Fund’s Investment
Objectives, Principal Strategies and Principal Risks^‡ — continued

There is widespread concern about the potential effects of
global climate change on property and security values. Certain issuers, industries and regions may be adversely affected by the impact of climate change in ways that cannot be foreseen. The impact of legislation, regulation and international accords
related to climate change may negatively impact certain issuers and/or industries.

Risks Associated with Active Management. The success of the Fund’s investment strategy depends on portfolio management’s successful application of analytical skills and investment judgment. Active management involves subjective decisions and there
is no guarantee that such decisions will produce the desired results or expected returns.

Tax Risk. Income from
tax-exempt municipal obligations could be declared taxable because of changes in tax laws, adverse interpretations by the relevant taxing authority or the non-compliant conduct of the issuer of an obligation.

Futures Risk. Although some
futures contracts call for making or taking delivery of the underlying reference instrument, generally these obligations are closed out prior to delivery by offsetting purchases or sales of matching futures contracts (same exchange, underlying
security or index, and delivery month). Closing a futures contract sale is effected by purchasing a futures contract for the same aggregate amount of the specific type of financial instrument or commodity with the same delivery date. If an
offsetting purchase price is less than the original sale price, the Fund realizes a capital gain, or if it is more, the Fund realizes a capital loss. Conversely, if an offsetting sale price is more than the original purchase price, the Fund realizes
a capital gain, or if it is less, the Fund realizes a capital loss. The Fund’s investment adviser has claimed an exclusion from the definition of a Commodity Pool Operator under the Commodity Exchange Act with respect to the Fund and
therefore, neither the Fund’s investment adviser nor the Fund are subject to registration or regulation thereunder.

Geopolitical Risk. The
increasing interconnectivity between global economies and financial markets increases the likelihood that events or conditions in one region or financial market may adversely impact issuers in a different country, region or financial market.
Securities in a Fund’s portfolio may underperform due to inflation (or expectations for inflation), interest rates, global demand for particular products or resources, natural disasters, health emergencies (such as epidemics and pandemics),
terrorism, regulatory events and governmental or quasi-governmental actions. The occurrence of global events similar to those in recent years, such as terrorist attacks around the world, natural disasters, health emergencies, social and political
discord, war or debt crises and downgrades, among others, may result in market volatility and may have short and/or long term effects on both the U.S. and global financial markets. Other financial, economic and other global market and social
developments or disruptions may result in similar adverse circumstances, and it is difficult to predict when similar events affecting the U.S. or global financial markets may occur, the effects that such events may have and the duration of those
effects (which may last for extended periods).

Such global events may negatively impact broad segments of
businesses and populations, cause a significant negative impact on the performance of the Fund’s investments, adversely affect and increase the volatility of the Fund’s share price, and/or exacerbate preexisting political, social and
economic risks to the Fund. The Fund’s operations may be interrupted and any such event(s) could have a significant adverse impact on the value and risk profile of the Fund’s portfolio. There is a risk that you may lose money by
investing in the Fund.

Tax-Sensitive Investing Risk. The Fund may hold a security in order to achieve more favorable tax-treatment or to sell a security in order to create tax losses. The Fund’s utilization of various tax-management techniques may be curtailed or
eliminated by tax legislation, regulation or interpretations. The Fund may not be able to minimize taxable distributions to shareholders and a portion of the Fund’s distributions may be taxable.

Cybersecurity Risk. With the
increased use of technologies by Fund service providers to conduct business, such as the Internet, the Fund is susceptible to operational, information security and related risks. In general, cyber incidents can result from deliberate attacks or
unintentional events. Cybersecurity failures by or breaches of the Fund’s investment adviser or administrator and other service providers (including, but not limited to, the custodian or transfer agent), and the issuers of securities in which
the Fund invests, may disrupt and otherwise adversely affect their business operations. This may result in financial losses to the Fund, impede Fund trading, interfere with the Fund’s ability to calculate its net asset value, interfere with
Fund shareholders’ ability to transact business or cause violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, reimbursement or other compensation costs, or additional compliance costs.

When-Issued and Delayed-Delivery Transactions Risk. Securities may be purchased on a “forward commitment,” “when-issued” or “delayed delivery” basis (meaning securities are purchased or sold with payment and delivery taking place in
the future) in order to secure what is considered to be an advantageous price and yield at the time of entering into the transaction. When the Fund agrees to purchase such securities, it assumes the risk of any decline in value of the security from
the date of the agreement to purchase. The Fund does not earn interest on the securities it has committed to purchase until they are paid for and delivered on the settlement date. From the time of entering into the transaction until delivery and
payment is made at a later date, the securities that are the subject of the transaction are subject to market fluctuations. In forward commitment, when-issued or delayed delivery transactions, if the seller or buyer, as the case may be, fails to
consummate the transaction the counterparty may miss the opportunity of obtaining a price or yield considered to be advantageous. However, no payment or delivery is made until payment is received or delivery is made from the other party to the
transaction. Such transactions may be considered a form of leverage.

Pooled Investment Vehicles
Risk. Pooled investment vehicles are open- and closed-end investment companies and exchange-traded funds (“ETFs”). Pooled investment vehicles are subject to the risks of investing in the underlying
securities or other investments. Shares of closed-end investment companies and ETFs may trade at a premium or discount to net asset value and are subject to secondary market trading risks. In addition, the Fund will bear a pro rata portion of the
operating expenses of a pooled investment vehicle in which it invests.

See Endnotes and Additional Disclosures in this report.

11

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

The Fund’s Investment
Objectives, Principal Strategies and Principal Risks^‡ — continued

Market Disruption. Global
instability, war, geopolitical tensions and terrorist attacks in the United States and around the world have previously resulted, and may in the future result in market volatility and may have long-term effects on the United States and worldwide
financial markets and may cause further economic uncertainties in the United States and worldwide. The Fund cannot predict the effects of significant future events on the global economy and securities markets. A similar disruption of the financial
markets could impact interest rates, auctions, secondary trading, ratings, credit risk, inflation and other factors relating to the common shares.

Swaps Risk. Swap agreements are
two-party contracts entered into primarily by institutional investors for periods ranging from a few weeks to more than one year. In a standard “swap” transaction, two parties agree to exchange the returns (or differentials in rates of
return) earned or realized on a particular predetermined reference instrument or instruments, which can be adjusted for an interest rate factor. The gross returns to be exchanged or “swapped” between the parties are generally calculated
with respect to a “notional amount” (i.e., the return on or increase in value of a particular dollar amount invested at a particular interest rate or in a “basket” of securities representing a particular index). Other types
of swap agreements may calculate the obligations of the parties to the agreement on a “net basis.” Consequently, a party’s current obligations (or rights) under a swap agreement will generally be equal only to the net amount to be
paid or received under the agreement based on the relative values of the positions held by each party to the agreement (the “net amount”). Whether the use of swap agreements will be successful will depend on the Adviser’s ability
to predict correctly whether certain types of reference instruments are likely to produce greater returns than other instruments. Swap agreements may be subject to contractual restrictions on transferability and termination and they may have terms
of greater than seven days. The Fund’s obligations under a swap agreement will be accrued daily (offset against any amounts owed to the Fund under the swap). Developments in the swaps market, including potential government regulation, could
adversely affect the Fund’s ability to terminate existing swap agreements or to realize amounts to be received under such agreements, as well as to participate in swap agreements in the future. If there is a default by the counterparty to a
swap, the Fund will have contractual remedies pursuant to the swap agreement, but any recovery may be delayed depending on the circumstances of the default.

Duration and Maturity Risk.
Holding long duration and long maturity investments will expose the Fund to certain magnified risks. These risks include interest rate risk, credit risk and liquidity risks as discussed above.

Hedging Risk. The Fund’s
use of derivatives or other transactions to reduce risks involves costs and will be subject to Eaton Vance’s ability to predict correctly changes in the relationships of such hedge instruments to the Fund’s portfolio holdings or other
factors. No assurance can be given that Eaton Vance’s judgment in this respect will be correct. In addition, no assurance can be given that the Fund will enter into hedging or other transactions at times or under circumstances in which it may
be advisable to do so. Hedging transactions have risks, including the imperfect correlation between the value of such instruments and the underlying assets of the Fund, which creates the possibility that the loss on such instruments may be greater
than the gain, if any, in the value of the underlying asset in the Fund’s portfolio; the limited availability of such instruments; the loss of principal; the possible default of the other party to the transaction; illiquidity of the derivative
investments; and the imperfect correlation between the tax-exempt and taxable markets. Furthermore, the ability to successfully use hedging transactions depends on the Eaton Vance’s ability to predict pertinent market movements, which cannot
be assured. Thus, the use of hedging transactions may result in losses greater than if they had not been used, may require the Fund to sell or purchase portfolio investments at inopportune times or for prices other than current market values, may
limit the amount of appreciation the Fund can realize on an investment, or may cause the Fund to hold a security that it might otherwise sell.

Anti-Takeover Provisions. The
Fund’s Agreement and Declaration of Trust and Amended and Restated By-Laws include provisions that could have the effect of making it more difficult to acquire control of the Fund or to change the composition of its Board.

General Fund Investing Risks.
The Fund is not a complete investment program and there is no guarantee that the Fund will achieve its investment objective. It is possible to lose money by investing in the Fund. An investment in the Fund is not a
deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

There have been no material changes to the Fund’s
investment objective or principal investment strategies since March 31, 2025.

See Endnotes and Additional Disclosures in this report.

12

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Endnotes and
Additional Disclosures

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Portfolio of
Investments — continued

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Portfolio of
Investments — continued

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Portfolio of
Investments — continued

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Portfolio of
Investments — continued

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Portfolio of
Investments — continued

19

See Notes to Financial Statements.

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Statement of Assets
and Liabilities

20

See Notes to Financial Statements.

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

21

See Notes to Financial Statements.

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Statements of Changes
in Net Assets

22

See Notes to Financial Statements.

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

23

See Notes to Financial Statements.

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

24

See Notes to Financial Statements.

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Notes to Financial
Statements

1  Significant Accounting Policies

Eaton Vance National Municipal Opportunities Trust (the Trust)
is a Massachusetts business trust registered under the Investment Company Act of 1940, as amended (the 1940 Act), as a diversified, closed-end management investment company. The Trust’s primary investment objective is to provide current income
exempt from regular federal income tax. The Trust will, as a secondary investment objective, seek to achieve capital appreciation.

The following is a summary of significant accounting policies
of the Trust. The policies are in conformity with accounting principles generally accepted in the United States of America (U.S. GAAP). The Trust is an investment company and follows accounting and reporting guidance in the Financial Accounting
Standards Board (FASB) Accounting Standards Codification Topic 946. 

A  Investment
Valuation—The following methodologies are used to determine the market value or fair value of
investments.

Debt Obligations. Debt obligations are generally valued on the basis of valuations provided by third party pricing services, as derived from such services’ pricing models. Inputs to the models may include, but are not limited to,
reported trades, executable bid and ask prices, broker/dealer quotations, prices or yields of securities with similar characteristics, interest rates, anticipated prepayments, benchmark curves or information pertaining to the issuer, as well as
industry and economic events. The pricing services may use a matrix approach, which considers information regarding securities with similar characteristics to determine the valuation for a security. Short-term debt obligations purchased with a
remaining maturity of sixty days or less for which a valuation from a third party pricing service is not readily available may be valued at amortized cost, which approximates fair value.

Other. Investments in
management investment companies (including money market funds) that do not trade on an exchange are valued at the net asset value as of the close of each business day.

Fair Valuation. In connection
with Rule 2a-5 of the 1940 Act, the Trustees have designated the Trust’s investment adviser as its valuation designee. Investments for which valuations or market quotations are not readily available or are deemed unreliable are valued by the
investment adviser, as valuation designee, at fair value using methods that most fairly reflect the security’s “fair value”, which is the amount that the Trust might reasonably expect to receive for the security upon its current
sale in the ordinary course. Each such determination is based on a consideration of relevant factors, which are likely to vary from one pricing context to another. These factors may include, but are not limited to, the type of security, the
existence of any contractual restrictions on the security’s disposition, the price and extent of public trading in similar securities of the issuer or of comparable companies or entities, quotations or relevant information obtained from
broker/dealers or other market participants, information obtained from the issuer, analysts, and/or the appropriate stock exchange (for exchange-traded securities), an analysis of the company’s or entity’s financial statements, and an
evaluation of the forces that influence the issuer and the market(s) in which the security is purchased and sold.

B  Investment Transactions and Related Income—Investment transactions for financial statement purposes are accounted for on a trade date basis. Realized
gains and losses on investments sold are determined on the basis of identified cost. Interest income is recorded on the basis of interest accrued, adjusted for amortization of premium or accretion of discount. Dividend income is recorded on the
ex-dividend date for dividends received in cash and/or securities.

C  Federal and Other Taxes—The Trust’s policy is to comply with the provisions of the Internal Revenue Code applicable to
regulated investment companies and to distribute to shareholders each year substantially all of its taxable, if any, and tax-exempt net investment income, and all or substantially all of its net realized capital gains. Accordingly, no provision for
federal income or excise tax is necessary. The Trust intends to satisfy conditions which will enable it to designate distributions from the interest income generated by its investments in non-taxable municipal securities, which are exempt from
regular federal income tax when received by the Trust, as exempt-interest dividends. The portion of such interest, if any, earned on private activity bonds issued after August 7, 1986, may be considered a tax preference item to shareholders. As of March 31, 2026, the Trust had no uncertain tax positions that would require financial statement recognition, de-recognition, or disclosure. The Trust files a U.S. federal income tax return annually after its fiscal
year-end, which is subject to examination by the Internal Revenue Service for a period of three years from the date of filing.

During this reporting period, the Trust adopted FASB Accounting
Standards Update No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (ASU 2023-09), which requires annual disclosure of the amount of income taxes paid (net of refunds received)
disaggregated by federal, state, and foreign taxes, and further disaggregated by individual jurisdiction in which income taxes paid is equal to or greater than 5% of total income taxes paid.

The adoption of ASU 2023-09 did not result in any changes to the Trust’s
financial statement presentation or disclosure.

D  Legal Fees— Legal fees and other related expenses incurred as part of negotiations of the terms and requirement of capital infusions, or that are expected
to result in the restructuring of, or a plan of reorganization for, an investment are recorded as realized losses. Ongoing expenditures to protect or enhance an investment are treated as operating expenses.

E  Use of
Estimates—The preparation of the financial statements in conformity with U.S. GAAP requires management
to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of income and expense during the reporting period. Actual results could differ from those
estimates.

F  Indemnifications—Under the Trust’s organizational documents, its officers and Trustees may be indemnified against certain
liabilities and expenses arising out of the performance of their duties to the Trust. Under Massachusetts law, if certain conditions prevail, shareholders of a Massachusetts business

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Notes to Financial
Statements — continued

trust (such as the
Trust) could be deemed to have personal liability for the obligations of the Trust. However, the Trust’s Declaration of Trust contains an express disclaimer of liability on the part of Trust shareholders and the By-laws provide that the Trust shall
assume, upon request by the shareholder, the defense on behalf of any Trust shareholders. Moreover, the By-laws also provide for indemnification out of Trust property of any shareholder held personally liable solely by reason of being or having been
a shareholder for all loss or expense arising from such liability. Additionally, in the normal course of business, the Trust enters into agreements with service providers that may contain indemnification clauses. The Trust’s maximum exposure
under these arrangements is unknown as this would involve future claims that may be made against the Trust that have not yet occurred.

G  Floating Rate Notes Issued in Conjunction with
Securities Held—The Trust may invest in residual interest bonds, also referred to as inverse floating
rate securities, whereby the Trust may sell a variable or fixed rate bond for cash to a Special-Purpose Vehicle (the SPV), (which is generally organized as a trust), while at the same time, buying a residual interest in the assets and cash flows of
the SPV. The bond is deposited into the SPV with the same CUSIP number as the bond sold to the SPV by the Trust, and which may have been, but is not required to be, the bond purchased from the Trust (the Bond). The SPV also issues floating rate
notes (Floating Rate Notes) which are sold to third-parties. The residual interest bond held by the Trust gives the Trust the right (1) to cause the holders of the Floating Rate Notes to generally tender their notes at par, and (2) to have the Bond
held by the SPV transferred to the Trust, thereby terminating the SPV. Should the Trust exercise such right, it would generally pay the SPV the par amount due on the Floating Rate Notes and exchange the residual interest bond for the underlying
Bond. Pursuant to generally accepted accounting principles for transfers and servicing of financial assets and extinguishment of liabilities, the Trust accounts for the transaction described above as a secured borrowing by including the Bond in its
Portfolio of Investments and the Floating Rate Notes as a liability under the caption “Payable for floating rate notes issued” in its Statement of Assets and Liabilities. The Floating Rate Notes have interest rates that generally reset
weekly and their holders have the option to tender their notes to the SPV for redemption at par at each reset date. Accordingly, the fair value of the payable for floating rate notes issued approximates its carrying value. If measured at fair value,
the payable for floating rate notes would have been considered as Level 2 in the fair value hierarchy (see Note 6) at March 31, 2026. Interest expense related to the Trust’s liability with respect to Floating Rate Notes is recorded as incurred. The
SPV may be terminated by the Trust, as noted above, or by the occurrence of certain termination events as defined in the trust agreement, such as a downgrade in the credit quality of the underlying Bond, bankruptcy of or payment failure by the
issuer of the underlying Bond, the inability to remarket Floating Rate Notes that have been tendered due to insufficient buyers in the market, or the failure by the SPV to obtain renewal of the liquidity agreement under which liquidity support is
provided for the Floating Rate Notes up to one year. At March 31, 2026 the amount of the Trust’s Floating Rate Notes outstanding and the related collateral were $40,297,292 and $52,323,032, respectively. The range of interest rates on the Floating
Rate Notes outstanding at March 31, 2026 was 2.42% to 2.59%. For the year ended March 31, 2026, the Trust’s average settled Floating Rate Notes outstanding and the average interest rate including fees were $39,359,726 and 3.05%,
respectively.

In certain circumstances, the Trust
may enter into shortfall and forbearance agreements with brokers by which the Trust agrees to reimburse the broker for the difference between the liquidation value of the Bond held by the SPV and the liquidation value of the Floating Rate Notes, as
well as any shortfalls in interest cash flows. The Trust had no shortfalls as of March 31, 2026.

The Trust may also purchase residual interest bonds in a
secondary market transaction without first owning the underlying bond. Such transactions are not required to be treated as secured borrowings. Shortfall agreements, if any, related to residual interest bonds purchased in a secondary market
transaction are disclosed in the Portfolio of Investments.

The Trust’s investment policies and restrictions
expressly permit investments in residual interest bonds. Such bonds typically offer the potential for yields exceeding the yields available on fixed rate bonds with comparable credit quality and maturity. These securities tend to underperform the
market for fixed rate bonds in a rising long-term interest rate environment, but tend to outperform the market for fixed rate bonds when long-term interest rates decline. The value and income of residual interest bonds are generally more volatile
than that of a fixed rate bond. The Trust’s investment policies do not allow the Trust to borrow money except as permitted by the 1940 Act. Effective August 19, 2022, the Trust began operating under Rule 18f-4 under the 1940 Act, which, among
other things, governs the use of derivative investments and certain financing transactions by registered investment companies. Consistent with Rule 18f-4, the Trust may treat its investments in residual interest bonds and similar financing
transactions as subject to the asset coverage requirements of Section 18 of the 1940 Act, or as derivatives transactions subject to the Trust’s value-at-risk (VaR)-based limits on leverage risk. Effective October 11, 2023, the Trust has opted
to treat such investments as derivatives transactions. The Trust may change this approach at any time. Residual interest bonds held by the Trust are securities exempt from registration under Rule 144A of the Securities Act of 1933.

H  Segment
Reporting—The Trust operates as a single reportable segment, an investment company whose investment
objective(s) is included in Note 1. The Trust’s President acts as the Trust’s Chief Operating Decision Maker (CODM), who is responsible for assessing the performance of the Trust’s single segment and deciding how to allocate the
segment’s resources. To perform this function, the CODM reviews the information in the Trust’s financial statements.

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Notes to Financial
Statements — continued

2  Distributions to Shareholders and Income Tax
Information

The Trust intends to make monthly
distributions of net investment income to common shareholders. In addition, at least annually, the Trust intends to distribute all or substantially all of its net realized capital gains. Distributions are recorded on the ex-dividend date.
Distributions to shareholders are determined in accordance with income tax regulations, which may differ from U.S. GAAP. As required by U.S. GAAP, only distributions in excess of tax basis earnings and profits are reported in the financial
statements as a return of capital. Permanent differences between book and tax accounting relating to distributions are reclassified to paid-in capital. For tax purposes, distributions from short-term capital gains are considered to be from ordinary
income.

The tax character of distributions declared for
the years ended March 31, 2026 and March 31, 2025 was as follows:

As of March 31, 2026, the components of distributable earnings
(accumulated loss) on a tax basis were as follows:

At March 31, 2026, the Trust, for
federal income tax purposes, had deferred capital losses of $25,187,726 which would reduce its taxable income arising from future net realized gains on investment transactions, if any, to the extent permitted by the Internal Revenue Code, and thus
would reduce the amount of distributions to shareholders, which would otherwise be necessary to relieve the Trust of any liability for federal income or excise tax. The deferred capital losses are treated as arising on the first day of the
Trust’s next taxable year and retain the same short-term or long-term character as when originally deferred. Of the deferred capital losses at March 31, 2026, $9,607,712 are short-term and $15,580,014 are long-term.

The cost and unrealized appreciation (depreciation) of
investments of the Trust at March 31, 2026, as determined on a federal income tax basis, were as follows:

3  Investment Adviser and Administrative Fee and
Other Transactions with Affiliates

The investment adviser
and administrative fee is earned by Eaton Vance Management (EVM), an indirect, wholly-owned subsidiary of Morgan Stanley, as compensation for investment advisory and administrative services rendered to the Trust. The fee is computed at an annual
rate as a percentage of the Trust’s average daily gross assets as follows and is payable monthly:

Gross assets, as defined in the
Trust’s investment advisory and administrative agreement with EVM, means total assets of the Trust, including any form of investment leverage, minus all accrued expenses incurred in the normal course of operations, but not excluding any
liabilities or obligations attributable to

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Notes to Financial
Statements — continued

investment leverage
obtained through (i) indebtedness of any type (including, without limitation, borrowing through a credit facility or the issuance of debt securities), (ii) the issuance of preferred stock or other similar preference securities, (iii) the
reinvestment of collateral received for securities loaned in accordance with the Trust’s investment objectives and policies, and/or (iv) any other means. For purposes of this calculation, gross assets represent net assets plus the amount
payable by the Trust to floating-rate note holders. For the year ended March 31, 2026, the investment adviser and administrative fee incurred by the Trust and the effective annual rate, as a percentage of average daily gross assets, were $1,913,167
and 0.60%, respectively.

Trustees and officers of the
Trust who are members of EVM’s organization receive remuneration for their services to the Trust out of the investment adviser and administrative fee. Trustees of the Trust who are not affiliated with the investment adviser may elect to defer
receipt of all or a percentage of their annual fees in accordance with the terms of the Trustees Deferred Compensation Plan. Certain officers and Trustees of the Trust are officers of EVM.

4  Purchases and Sales of Investments

Purchases and sales of investments, other than short-term
obligations, aggregated $104,244,132 and $110,652,775, respectively, for the year ended March 31, 2026.

5  Common Shares of Beneficial Interest and Shelf
Offering

The Trust may issue common shares pursuant to
its dividend reinvestment plan. There were no common shares issued by the Trust for the years ended March 31, 2026 and March 31, 2025.

In November 2013, the Board of Trustees initially approved a
share repurchase program for the Trust. Pursuant to the reauthorization of the share repurchase program by the Board of Trustees in March 2019, the Trust is authorized to repurchase up to 10% of its common shares outstanding as of the last day of
the prior calendar year at market prices when shares are trading at a discount to net asset value. The share repurchase program does not obligate the Trust to purchase a specific amount of shares. There were no repurchases of common shares by the
Trust for the years ended March 31, 2026 and March 31, 2025.

In July 2022, the Trust filed an automatically effective shelf
registration statement (the 2022 Registration Statement) and a prospectus supplement, pursuant to the 2022 Registration Statement, relating to the offer and sale of up to an additional 1,908,750 common shares of the Trust under the Trust’s then
current equity shelf offering program. As of July 2025, the offering of unsold shares pursuant to the 2022 Registration Statement has been terminated. During the years ended March 31, 2026 and March 31, 2025, there were no shares sold by the
Trust pursuant to its shelf offering.

6  Fair
Value Measurements

Under generally accepted accounting
principles for fair value measurements, a three-tier hierarchy to prioritize the assumptions, referred to as inputs, is used in valuation techniques to measure fair value. The three-tier hierarchy of inputs is summarized in the three broad levels
listed below.

In cases where the inputs used to measure fair value fall in
different levels of the fair value hierarchy, the level disclosed is determined based on the lowest level input that is significant to the fair value measurement in its entirety. The inputs or methodology used for valuing securities are not
necessarily an indication of the risk associated with investing in those securities.

At March 31, 2026, the hierarchy of inputs used in valuing the
Trust’s investments, which are carried at fair value, were as follows:

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Report of Independent
Registered Public Accounting Firm

To the
Trustees and Shareholders of Eaton Vance National Municipal Opportunities Trust:

Opinion on the Financial Statements and Financial
Highlights

We have audited the accompanying statement of
assets and liabilities of Eaton Vance National Municipal Opportunities Trust (the “Trust”), including the portfolio of investments, as of March 31, 2026, the related statements of operations and cash flows for the year then ended, the
statements of changes in net assets for each of the two years in the period then ended, the financial highlights for each of the five years in the period then ended, and the related notes (collectively referred to as the “financial statements
and financial highlights”). In our opinion, the financial statements and financial highlights present fairly, in all material respects, the financial position of the Trust as of March 31, 2026, and the results of its operations and its cash
flows for the year then ended, the changes in its net assets for each of the two years in the period then ended, and the financial highlights for each of the five years in the period then ended, in conformity with accounting principles generally
accepted in the United States of America.

Basis for
Opinion

These financial statements and financial
highlights are the responsibility of the Trust’s management. Our responsibility is to express an opinion on the Trust’s financial statements and financial highlights based on our audits. We are a public accounting firm registered with the
Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Trust in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and
Exchange Commission and the PCAOB.

We conducted our
audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements and financial highlights are free of material misstatement,
whether due to error or fraud. The Trust is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits, we are required to obtain an understanding of internal control over
financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Trust’s internal control over financial reporting. Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks
of material misstatement of the financial statements and financial highlights, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts
and disclosures in the financial statements and financial highlights. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial
statements and financial highlights. Our procedures included confirmation of securities owned as of March 31, 2026, by correspondence with the custodian and brokers; when replies were not received from brokers, we performed other auditing
procedures. We believe that our audits provide a reasonable basis for our opinion.

/s/ Deloitte & Touche LLP
Boston, Massachusetts
May 21, 2026

We have served as the auditor of one or
more Eaton Vance investment companies since 1959.

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Federal Tax
Information (Unaudited)

The
Form 1099-DIV you receive in February 2027 will show the tax status of all distributions paid to your account in calendar year 2026. Shareholders are advised to consult their own tax adviser with respect to the tax consequences of their
investment in the Trust. As required by the Internal Revenue Code and/or regulations, shareholders must be notified regarding the status of exempt-interest dividends.

Exempt-Interest Dividends. For
the fiscal year ended March 31, 2026, the Trust designates 92.10% of distributions from net investment income as an exempt-interest dividend.

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Annual Meeting of
Shareholders (Unaudited)

The
Trust held its Annual Meeting of Shareholders on January 7, 2026. The following action was taken by the shareholders:

Proposal 1(b): The election of Cynthia E. Frost, Keith Quinton
and Nancy Wiser Stefani as Class II Trustees of the Trust for a three-year term expiring in 2029.

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Dividend Reinvestment
Plan

The Trust offers a dividend reinvestment plan (Plan) pursuant
to which shareholders automatically have distributions reinvested in common shares (Shares) of the Trust unless they elect otherwise through their investment dealer. On the distribution payment date, if the NAV per Share is equal to or less than the
market price per Share plus estimated brokerage commissions, then new Shares will be issued. The number of Shares shall be determined by the greater of the NAV per Share or 95% of the market price. Otherwise, Shares generally will be purchased on
the open market by Equiniti Trust Company, LLC (“EQ”), the Plan agent (Agent). Distributions subject to income tax (if any) are taxable whether or not Shares are reinvested.

If your Shares are in the name of a brokerage firm, bank, or
other nominee, you can ask the firm or nominee to participate in the Plan on your behalf. If the nominee does not offer the Plan, you will need to request that the Trust’s transfer agent re-register your Shares in your name or you will not be able
to participate.

The Agent’s service fee for
handling distributions will be paid by the Trust. Plan participants will be charged their pro rata share of brokerage commissions on all open-market purchases.

Plan participants may withdraw from the Plan at any time by
writing to the Agent at the address noted on the following page. If you withdraw, you will receive Shares in your name for all Shares credited to your account under the Plan. If a participant elects by written notice to the Agent to sell part or all
of his or her Shares and remit the proceeds, the Agent is authorized to deduct a $5.00 fee plus brokerage commissions from the proceeds.

If you wish to participate in the Plan and your Shares are held
in your own name, you may complete the form on the following page and deliver it to the Agent. Any inquiries regarding the Plan can be directed to the Agent at 1-866-439-6787.

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Application for
Participation in Dividend Reinvestment Plan

The following authorization and appointment
is given with the understanding that I may terminate it at any time by terminating my participation in the Plan as provided in the terms and conditions of the Plan.

YOU SHOULD NOT RETURN THIS FORM IF YOU WISH TO
RECEIVE YOUR DISTRIBUTIONS IN CASH. THIS IS NOT A PROXY.

This authorization form, when signed, should
be mailed to the following address:

Eaton Vance National Municipal
Opportunities Trust
c/o Equiniti Trust Company, LLC (“EQ”)
P.O. Box 10027
Newark, NJ 07101

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Management and
Organization

Fund
Management. The Board of Trustees of the Fund (the “Board”) is responsible for the overall management and supervision of the affairs of the Fund. The Board members and officers of the Fund are listed
below. Except as indicated, each individual has held the office shown or other offices in the same company for the last five years. Each Trustee holds office until the annual meeting for the year in which his or her term expires and until his or her
successor is elected and qualified, subject to a prior death, resignation, retirement, disqualification or removal. Under the terms of the Fund’s current Trustee retirement policy, an Independent Trustee must retire and resign as a Trustee on
the earlier of: (i) the first day of July following his or her 76th birthday; or (ii), with limited exception, December 31st of the 20th year in which he or she has served as a Trustee. However, if such retirement and resignation would cause the
Fund to be out of compliance with Section 16 of the 1940 Act or any other regulations or guidance of the Securities and Exchange Commission, then such retirement and resignation will not become effective until such time as action has been taken for
the Fund to be in compliance therewith. The “noninterested Trustees” consist of those Trustees who are not “interested persons” of the Fund, as that term is defined under the 1940 Act. The business address of each Board
member and officer is One Post Office Square, Boston, Massachusetts 02109. As used below, “BMR” refers to Boston Management and Research, “EV” refers to EV LLC, “EVM” refers to Eaton Vance Management,
“MSIM” refers to Morgan Stanley Investment Management Inc. and “EVD” refers to Eaton Vance Distributors, Inc. EV is the trustee of each of EVM and BMR. Each of EVM, BMR, EVD and EV are indirect, wholly owned subsidiaries
of Morgan Stanley. Each officer affiliated with EVM may hold a position with other EVM affiliates that is comparable to his or her position with EVM listed below. Each Trustee oversees 123 funds in the Eaton Vance fund complex (including both funds
and portfolios in a hub and spoke structure). 

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Management and
Organization — continued

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Potential Conflicts of
Interest

As a
diversified global financial services firm, Morgan Stanley, the parent company of the investment adviser, engages in a broad spectrum of activities, including financial advisory services, investment management activities, lending, commercial
banking, sponsoring and managing private investment funds, engaging in broker-dealer transactions and principal securities, commodities and foreign exchange transactions, research publication and other activities. In the ordinary course of its
business, Morgan Stanley is a full-service investment banking and financial services firm and therefore engages in activities where Morgan Stanley’s interests or the interests of its clients may conflict with the interests of a Fund or
Portfolio, if applicable, (collectively for the purposes of this section, “Fund” or “Funds”). Morgan Stanley advises clients and sponsors, manages or advises other investment funds and investment programs, accounts and
businesses (collectively, together with any new or successor funds, programs, accounts or businesses sponsored, managed, or advised by the investment adviser or one of its investment adviser affiliates, the “Affiliated Investment
Accounts”) with a wide variety of investment objectives that in some instances may overlap or conflict with a Fund’s investment objectives and present conflicts of interest. In addition, Morgan Stanley, the investment adviser and/or the
investment adviser’s investment adviser affiliates may also from time to time create new or successor Affiliated Investment Accounts that may compete with a Fund and present similar conflicts of interest. The discussion below enumerates
certain actual, apparent and potential conflicts of interest. There is no assurance that conflicts of interest will be resolved in favor of Fund shareholders and, in fact, they may not be. The conflicts herein do not purport to be a complete list or
explanation of the conflicts associated with the financial or other interests the investment adviser or its affiliates may have now or in the future. Conflicts of interest not described below may also exist. References to the investment adviser in
this section include a Fund’s affiliated sub-adviser (if any) unless otherwise noted.

The discussions below with respect to actual, apparent and
potential conflicts of interest may be applicable to or arise from the Affiliated Investment Accounts managed by the investment adviser’s investment adviser affiliates whether or not specifically identified.

Material Non-Public and Other Information. It is expected that confidential or material non-public information regarding an investment or potential investment opportunity may become available to the investment adviser. If such information becomes available, the
investment adviser may be precluded (including by applicable law or internal policies or procedures) from pursuing an investment or disposition opportunity with respect to such investment or disposition opportunity including for an extended period
of time. The investment adviser may also from time to time be subject to contractual “stand-still” obligations and/or confidentiality obligations that may restrict its ability to transact in certain investments on the Fund’s
behalf. In addition, the investment adviser may be precluded from disclosing such information to an investment team, even in circumstances in which the information would be beneficial if disclosed. Therefore, the investment team may not be provided
access to material non-public information in the possession of Morgan Stanley that might be relevant to an investment decision to be made on behalf of the Fund, and the investment team may initiate a transaction or sell an investment that, if such
information had been known to it, may not have been undertaken. In addition, certain members of the investment team may be recused from certain investment-related discussions so that such members do not receive information that would limit their
ability to perform functions of their employment with the investment adviser or its affiliates unrelated to that of the Fund. Furthermore, access to information held by certain parts of Morgan Stanley may be subject to third party confidentiality
obligations and to information barriers established by Morgan Stanley designed to manage potential conflicts of interest and regulatory restrictions, including, without limitation, joint transaction restrictions pursuant to the 1940 Act.
Accordingly, the investment adviser’s ability to source investments from, or invest alongside, other business units within Morgan Stanley may be limited and there can be no assurance that the investment adviser will be able to source any
investments from any one or more parts of the Morgan Stanley network.

The investment adviser may restrict its investment decisions
and activities on behalf of the Fund in various circumstances, including because of applicable regulatory requirements or information held by the investment adviser, the investment adviser’s investment adviser affiliates or Morgan Stanley. The
investment adviser might not engage in transactions or other activities for, or enforce certain rights in favor of, the Fund due to Morgan Stanley’s activities outside the Fund. Furthermore, Morgan Stanley could have an interest that is
different from, and potentially adverse to, that of the Fund, which may impede the Fund from participating in certain opportunities. In instances where trading of an investment is restricted, the investment adviser may not be able to purchase or
sell such investment on behalf of the Fund including for an extended period of time, resulting in the Fund’s inability to participate in certain desirable transactions. This inability to buy or sell an investment could have an adverse effect
on the Fund’s portfolio due to, among other things, changes in an investment’s value during the period its trading is restricted.

Morgan Stanley has established certain information barriers and
other policies designed to address the sharing of information between different businesses within Morgan Stanley. As a result of information barriers, the investment adviser, in certain instances, will not have access, or will have limited access,
to certain information and personnel in other areas of Morgan Stanley and, in such instances, will not manage the Fund with the benefit of the information held by such other areas. Morgan Stanley, due to its access to and knowledge of funds, markets
and securities based on its various businesses, may make decisions based on information or take (or refrain from taking) actions with respect to interests in investments of the kind held (directly or indirectly) by the Fund in a manner that may be
adverse to the Fund, and will not have any obligation or other duty to share information with the investment adviser.

In other instances, Morgan Stanley personnel, including
personnel of the investment adviser, will have access to information and personnel of its affiliates. For example, the investment adviser may, in certain instances, share information with its affiliates regarding due diligence of companies and other
investment-related due diligence. The investment adviser may face conflicts of interest in determining whether to engage in the sharing of information with its affiliates. Information sharing may limit or restrict the ability of the investment
adviser to engage in or otherwise effect transactions on behalf of the Fund (including purchasing or selling securities that the investment adviser may otherwise have purchased or sold for the Fund in the absence of the sharing of information).
Also, it may adversely affect the Fund’s investments, ability to invest in, or divest from, a company or engage in transactions or otherwise disadvantage the Fund. In managing conflicts of interest that arise because of the foregoing, the investment
adviser generally will be subject to fiduciary requirements. The investment adviser may also implement internal information barriers or ethical walls or other internal information sharing protocols, and the conflicts described herein with respect to
information barriers and otherwise with respect to Morgan Stanley and the investment adviser will also apply

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Potential Conflicts of
Interest — continued

internally within the
investment adviser. As a result, the Fund may not be permitted to transact in (e.g., dispose of a security in whole or in part) during periods when it otherwise would have been desirable and able to do so, which could adversely affect the Fund.
Other investors in the security that are not subject to such restrictions may be able to transact in the security during such periods. There may also be circumstances in which, as a result of information held by certain portfolio management teams in
the investment adviser, the investment adviser limits an activity or transaction for the Fund, including if the Fund is managed by a portfolio management team other than the team holding such information.

Morgan Stanley and its personnel will not be under any
obligation or other duty to share certain information with the investment adviser or personnel involved in decision-making for Affiliated Investment Accounts (including the Fund), as applicable, and the investment adviser may make investment
decisions for the Fund that differ from those the investment adviser would have made if Morgan Stanley, or other parts, of the investment adviser had provided such information, and the Fund be disadvantaged as a result thereof. Additionally,
different portfolio management teams within the investment adviser may make decisions based on information or take (or refrain from taking) actions with respect to Affiliated Investment Accounts they advise in a manner different than or adverse to
the Fund.

Investments by Morgan Stanley and its Affiliated
Investment Accounts. In serving in multiple capacities to Affiliated Investment Accounts, Morgan Stanley, including the investment adviser and its investment teams, may have obligations to other clients or investors
in Affiliated Investment Accounts, the fulfillment of which may not be in the best interests of the Fund or its shareholders. An investment team may have obligations to Affiliated Investment Accounts managed by both the investment adviser and one or
more of the investment adviser’s investment adviser affiliates. The Fund’s investment objectives may overlap with the investment objectives of certain Affiliated Investment Accounts. As a result, the members of an investment team may
face conflicts in the allocation of investment opportunities among the Fund and other investment funds, programs, accounts and businesses advised by or affiliated with the investment adviser or its investment adviser affiliates. Certain Affiliated
Investment Accounts may provide for higher management or incentive fees or greater expense reimbursements or overhead allocations, all of which may contribute to this conflict of interest and create an incentive for the investment adviser to favor
such other accounts.

Morgan Stanley currently
invests and plans to continue to invest on its own behalf and on behalf of its Affiliated Investment Accounts in a wide variety of investment opportunities globally. Morgan Stanley and its Affiliated Investment Accounts, to the extent consistent
with applicable law and policies and procedures, will be permitted to invest in investment opportunities without making such opportunities available to the Fund. Subject to the foregoing, Morgan Stanley may offer investments that fall into the
investment objectives of an Affiliated Investment Account to such account or make such investment on its own behalf, even though such investment also falls within the Fund’s investment objectives. The Fund may invest in opportunities that
Morgan Stanley and/or one or more Affiliated Investment Accounts has declined, and vice versa. All of the foregoing may reduce the number of investment opportunities available to the Fund and may create conflicts of interest in allocating investment
opportunities. Investors should note that the conflicts inherent in making such allocation decisions may not always be resolved to the Fund’s advantage. There can be no assurance that the Fund will have an opportunity to participate in certain
opportunities that fall within their investment objectives. The interests of Morgan Stanley in an investment or a company may present certain conflicts of interest with respect to an investment by the Fund in the same investment or the Fund’s
participation in a transaction with such company.

To the
extent the investment adviser utilizes quantitative models or risk management or optimization investment techniques, the decision on when to initiate a purchase or sale transaction may differ, and be done for different reasons, than the investment
adviser or its affiliates take on Affiliated Investment Accounts on the same securities when not utilizing such techniques. This could create conflicts of interest, and it is possible that one or more accounts managed by the investment adviser will
achieve investment results that are substantially more or less favorable than those results achieved by the Fund.

To seek to reduce potential conflicts of interest and to
attempt to allocate such investment opportunities in a fair and equitable manner, the investment adviser has implemented allocation policies and procedures. These policies and procedures are intended to give all clients of the investment adviser,
including the Fund, fair access to investment opportunities consistent with the requirements of organizational documents, investment strategies, applicable laws and regulations, and the fiduciary duties of the investment adviser. Each client of the
investment adviser that is subject to the allocation policies and procedures, including the Fund, is assigned an investment team and portfolio manager(s) by the investment adviser. The investment team and portfolio managers review investment
opportunities and will decide with respect to the allocation of each opportunity considering various factors and in accordance with the allocation policies and procedures. The allocation policies and procedures are subject to change. Investors
should note that the conflicts inherent in making such allocation decisions may not always be resolved to the advantage of the Fund.

It is possible that Morgan Stanley or an Affiliated Investment
Account, including another Morgan Stanley Fund, will invest in or advise (in the case of Morgan Stanley) a company that is or becomes a competitor of a company of which the Fund holds an investment. Such investment could create a conflict between
the Fund, on the one hand, and Morgan Stanley or the Affiliated Investment Account, on the other hand. In such a situation, Morgan Stanley may also have a conflict in the allocation of its own resources to the portfolio investment. Furthermore,
certain Affiliated Investment Accounts will be focused primarily on investing in other funds which may have strategies that overlap and/or directly conflict and compete with the Fund.

In addition, certain investment professionals who are involved
in the Fund’s activities remain responsible for the investment activities of other Affiliated Investment Accounts managed by the investment adviser and its affiliates, and they will devote time to the management of such investments and other
newly created Affiliated Investment Accounts (whether in the form of funds, separate accounts or other vehicles), as well as their own investments. In

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Potential Conflicts of
Interest — continued

addition, in
connection with the management of investments for other Affiliated Investment Accounts, members of Morgan Stanley and its affiliates may serve on the boards of directors of or advise companies which may compete with the Fund’s portfolio
investments. Moreover, these Affiliated Investment Accounts managed by Morgan Stanley and its affiliates may pursue investment opportunities that may also be suitable for the Fund.

It should be noted that Morgan Stanley may, directly or
indirectly, make large investments in certain of its Affiliated Investment Accounts, and accordingly Morgan Stanley’s investment in the Fund may not be a determining factor in the outcome of any of the foregoing conflicts. Nothing herein
restricts or in any way limits the activities of Morgan Stanley, including its ability to buy or sell interests in, or provide financing to, equity and/or debt instruments, funds or portfolio companies, for its own accounts or for the accounts of
Affiliated Investment Accounts or other investment funds or clients in accordance with applicable law.

Different clients of the investment adviser and its affiliates,
including the Fund, may invest in (1) different classes of securities of the same issuer (including, without limitation, different parts of an issuer’s capital structure), depending on the respective clients’ investment objectives and policies
and/or (2) the same class of securities of the same issuer while seeking different investment objectives or executing different investment strategies (such as long-term v. short-term investment horizons), and the investment adviser may face
conflicts with respect to the interests involved. As a result, the investment adviser and its affiliates, at times, will seek to satisfy fiduciary obligations to certain clients owning one / the same class of securities of a particular issuer by
pursuing or enforcing rights on behalf of those clients with respect to such (class of) securities, and those activities may have an adverse effect on another client which owns a different class of securities of such issuer. For example, if one
client holds debt securities of an issuer and another client holds equity securities of the same issuer, if the issuer experiences financial or operational challenges, the investment adviser and its affiliates may seek a liquidation of the issuer on
behalf of the client that holds the debt securities, whereas the client holding the equity securities may benefit from a reorganization of the issuer. Thus, in such situations, the actions taken by the investment adviser or its affiliates on behalf
of one client can negatively impact securities held by another client. Alternatively, for example, if a client owns a security while seeking short-term capital appreciation that investment adviser may vote proxies or engage with the issuer (as
applicable) in pursuit of that goal – which could negatively impact clients who hold the same security but are seeking long-term capital appreciation. These conflicts also exist as between the investment adviser’s clients, including the
Fund, and the Affiliated Investment Accounts managed by the investment adviser’s investment adviser affiliates.

In addition, in certain circumstances, the investment adviser
restricts, limits or reduces the amount of the Fund’s investment, or restricts the type of governance or voting rights it acquires or exercises, where the Fund (potentially together with Morgan Stanley) exceeds a certain ownership interest, or
possesses certain degrees of voting or control or has other interests.

The investment adviser and its affiliates may give advice and
recommend securities to other clients which may differ from advice given to, or securities recommended or bought for, the Fund even though such other clients’ investment objectives may be similar to those of the Fund and the investment adviser
may make decisions for the Fund that may be more beneficial to one type of shareholder than another.

The investment adviser and its affiliates manage long and short
portfolios. The simultaneous management of long and short portfolios creates conflicts of interest in portfolio management and trading in that opposite directional positions may be taken in client accounts, including client accounts managed by the
same investment team, and creates risks such as: (i) the risk that short sale activity could adversely affect the market value of long positions in one or more portfolios (and vice versa) and (ii) the risks associated with the trading desk receiving
opposing orders in the same security simultaneously. The investment adviser and its affiliates have adopted policies and procedures that are reasonably designed to mitigate these conflicts. In certain circumstances, the investment adviser invests on
behalf of itself in securities and other instruments that would be appropriate for, held by, or may fall within the investment guidelines of its clients, including the Fund. At times, the investment adviser may give advice or take action for its own
accounts that differs from, conflicts with, or is adverse to advice given or action taken for any client.

From time to time, conflicts also arise due to the fact that
certain securities or instruments may be held in some client accounts, including the Fund, but not in others, or that client accounts may have different amounts of holdings in certain securities or instruments. In addition, due to differences in the
investment strategies or restrictions among client accounts, the investment adviser may take action with respect to one account that differs from the action taken with respect to another account. In some cases, a client account may compensate the
investment adviser based on the performance of the securities held by that account or pay a higher overall fee rate. The existence of such a performance based fee or higher fee rates may create additional conflicts of interest for the investment
adviser in the allocation of management time, resources and investment opportunities. The investment adviser has adopted several policies and procedures designed to address these potential conflicts including a code of ethics and policies that
govern the investment adviser’s trading practices, including, among other things, the aggregation and allocation of trades among clients, brokerage allocations, cross trades and best execution.

In addition, at times an investment team will give advice or
take action with respect to the investments of one or more clients that is not given or taken with respect to other clients with similar investment programs, objectives, and strategies. Accordingly, clients with similar strategies will not always
hold the same securities or instruments or achieve the same performance. The investment adviser’s investment teams also advise clients with conflicting programs, objectives or strategies. These conflicts also exist as between the investment
adviser’s clients, including the Fund, and the Affiliated Investment Accounts managed by the investment adviser’s investment adviser affiliates.

From time to time, the investment adviser or its affiliates may
provide opportunities to Affiliated Investment Accounts (including potentially the Fund) or other clients to make investments in companies (such as in equity, debt or other securities issued by companies) or to engage in transactions involving
companies (such as refinancing, restructuring or other transactions) in which certain Affiliated Investment Accounts (including potentially the Fund) or other

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Potential Conflicts of
Interest — continued

clients have already
invested. These investments can create conflicts of interest, including those associated with the assets of the Fund potentially providing value to, or otherwise supporting the investments of, other Affiliated Investment Accounts or other clients
and potentially diluting or otherwise adversely affecting the Fund previously invested in the company.

Morgan Stanley and its affiliates maintain separate trading
desks that operate independently of each other and do not share information with the investment adviser. The Morgan Stanley and affiliate trading desks may compete against the investment adviser trading desks when implementing buy and sell
transactions, possibly causing certain Affiliated Investment Accounts to pay more or receive less for a security than other Affiliated Investment Accounts.

Investments by Separate Investment Departments. For the investment adviser and certain of its investment adviser affiliates, the entities and individuals that provide investment-related services can differ by client, investment function, or business line (each, an
“Investment Department” and collectively, the “Investment Departments”). Nonetheless, Investment Departments (with certain exceptions) can engage in discussions and share information and resources with another Investment
Department (or a team within the other Investment Department) regarding investment-related matters. The sharing of information and resources between the Investment Departments is designed to further increase the knowledge and effectiveness of each
Investment Department. However, an investment team’s decisions as to the use of shared research and participation in discussions with another Investment Department could adversely impact a client. Certain investment teams within one Investment
Department could make investment decisions and execute trades together with investment teams within other Investment Departments. Other investment teams make investment decisions and execute trades independently. This could cause the quality and
price of execution, and the performance of investments and accounts, to vary. Internal policies and procedures set forth the guidelines under which securities and securities trades can be crossed, aggregated, and coordinated between accounts
serviced by different Investment Departments. Internal policies and procedures take into consideration a variety of factors, including the primary market in which such security trades. If a security or securities trade is ineligible for crossing,
aggregation, or other coordinated trading, then each Investment Department will execute such trades independently of the other.

Payments to Broker-Dealers and Other Financial Intermediaries. The investment adviser, Eaton Vance Distributors, Inc. (the “Distributor”) and/or their affiliates may pay compensation, out of their own funds and not as an expense of the Fund, to certain Financial
Intermediaries (which may include affiliates of the investment adviser and the Distributor), including recordkeepers and administrators of various deferred compensation plans, in connection with the sale, distribution, marketing and retention of
shares of the Fund and/or shareholder servicing. For example, the investment adviser or the Distributor may pay additional compensation to a Financial Intermediary for, among other things, promoting the sale and distribution of Fund shares,
providing access to various programs, mutual fund platforms or preferred or recommended mutual fund lists that may be offered by a Financial Intermediary, granting the Distributor access to a Financial Intermediary’s financial advisors and
consultants, providing assistance in the ongoing education and training of a Financial Intermediary’s financial personnel, furnishing marketing support, maintaining share balances and/or for sub-accounting, recordkeeping, administrative,
shareholder or transaction processing services. Such payments are in addition to any distribution fees, shareholder servicing fees and/or transfer agency fees that may be payable by the Fund. The additional payments may be based on various factors,
including level of sales (based on gross or net sales or some specified minimum sales or some other similar criteria related to sales of the Fund and/or some or all other Morgan Stanley Funds), amount of assets invested by the Financial
Intermediary’s customers (which could include current or aged assets of the Fund and/or some or all other Morgan Stanley Funds), the Fund’s advisory fee, some other agreed upon amount or other measures as determined from time to time by
the investment adviser and/or the Distributor. The amount of these payments may be different for different Financial Intermediaries. In certain cases, payments to broker-dealers and other Financial Intermediaries may be shared by and among the
investment adviser, the Distributor and their affiliates.

The prospect of receiving, or the receipt of, additional
compensation, as described above, by Financial Intermediaries may provide such Financial Intermediaries and their financial advisors and other salespersons with an incentive to favor sales of shares of the Fund over other investment options with
respect to which these Financial Intermediaries do not receive additional compensation (or receives lower levels of additional compensation). These payment arrangements, however, will not change the price that an investor pays for shares of the Fund
or the amount that the Fund receives to invest on behalf of an investor. Investors may wish to take such payment arrangements into account when considering and evaluating any recommendations relating to Fund shares and should review carefully any
disclosures provided by Financial Intermediaries as to their compensation.

The additional compensation received by a given Financial
Intermediary from the investment adviser and/or the Distributor may vary from the additional compensation received by the Financial Intermediary in respect of an Affiliated Investment Account managed by an affiliate of the investment adviser or
principally underwritten by an affiliate of the Distributor. In such circumstances, differences in the prospect of receiving, or the receipt of, additional compensation, as described above, by Financial Intermediaries may provide such Financial
Intermediaries and their financial advisors and other salespersons with an incentive to favor sales of shares of one Affiliated Investment Account over other investment options with respect to which these Financial Intermediaries do not receive
additional compensation (or receives lower levels of additional compensation).

Morgan Stanley Trading and Principal Investing Activities. Notwithstanding anything to the contrary herein, Morgan Stanley will generally conduct its sales and trading businesses, publish research and analysis, and render investment advice without regard for the Fund’s
holdings, although these activities could have an adverse impact on the value of one or more of the Fund’s investments, or could cause Morgan Stanley to have an interest in one or more portfolio investments that is different from and
potentially adverse to that of the Fund. Furthermore, from time to time, the investment adviser or its affiliates may invest “seed” capital in a Fund, typically to enable such Fund to commence investment operations and/or achieve
sufficient scale, as further described below. The investment adviser and its affiliates may hedge such seed capital exposure by investing in derivatives or other instruments expected to produce offsetting exposure. Such hedging transactions, if any,
would occur outside of such Fund.

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Potential Conflicts of
Interest — continued

Morgan
Stanley’s sales and trading, financing and principal investing businesses (whether or not specifically identified as such, and including Morgan Stanley’s trading and principal investing businesses) will not be required to offer any
investment opportunities to the Fund. These businesses may encompass, among other things, principal trading activities as well as principal investing.

Morgan Stanley’s sales and trading, financing and
principal investing businesses have acquired or invested in, and in the future may acquire or invest in, minority and/or majority control positions in equity or debt instruments of diverse public and/or private companies. Such activities may put
Morgan Stanley in a position to exercise contractual, voting or creditor rights, or management or other control with respect to securities or loans of portfolio investments or other issuers, and in these instances Morgan Stanley may, in its
discretion and subject to applicable law, act to protect its own interests or interests of clients, and not the Fund’s interests.

Subject to the limitations of applicable law, the Fund may
purchase from or sell assets to, or make investments in, companies in which Morgan Stanley has or may acquire an interest, including as an owner, creditor or counterparty.

Morgan Stanley’s Investment Banking and Other Commercial
Activities. Morgan Stanley advises clients on a variety of mergers, acquisitions, restructuring, bankruptcy and financing transactions. Morgan Stanley may act as an advisor to clients, including other investment
funds that may compete with the Fund and with respect to investments that the Fund may hold. Morgan Stanley may give advice and take action with respect to any of its clients or proprietary accounts that may differ from the advice given, or may
involve an action of a different timing or nature than the action taken, by the Fund. Morgan Stanley may give advice and provide recommendations to persons competing with the Fund and/or any of the Fund’s investments that are contrary to the
Fund’s best interests and/or the best interests of any of its investments.

Morgan Stanley could be engaged in financial advising, whether
on the buy-side or sell-side, or in financing or lending assignments that could result in Morgan Stanley’s determining in its discretion or being required to act exclusively on behalf of one or more third parties, which could limit the
Fund’s ability to transact with respect to one or more existing or potential investments. Morgan Stanley may have relationships with third-party funds, companies or investors who may have invested in or may look to invest in portfolio
companies, and there could be conflicts between the Fund’s best interests, on the one hand, and the interests of a Morgan Stanley client or counterparty, on the other hand.

To the extent that Morgan Stanley advises companies in
financial restructurings outside of, prior to or after filing for protection under Chapter 11 of the U.S. Bankruptcy Code or similar laws in other jurisdictions, the investment adviser’s flexibility in making investments in such restructurings
on the Fund’s behalf, or participating on steering committees and other committees in connection with existing investments, may be limited.

Morgan Stanley could provide investment banking services to
competitors of portfolio companies, as well as to private equity and/or private credit funds; such activities may present Morgan Stanley with a conflict of interest vis-a-vis the Fund’s investment and may also result in a conflict in respect
of the allocation of investment banking resources to portfolio companies.

To the extent permitted by applicable law, Morgan Stanley may
provide a broad range of financial services to companies in which the Fund invests, including strategic and financial advisory services, interim acquisition financing and other lending and underwriting or placement of securities, and Morgan Stanley
generally will be paid fees (that may include warrants or other securities) for such services. Morgan Stanley will not share any of the foregoing interest, fees and other compensation received by it (including, for the avoidance of doubt, amounts
received by the investment adviser) with the Fund, and any advisory fees payable will not be reduced thereby.

Morgan Stanley may be engaged to act as a financial advisor to
a company in connection with the sale of such company, or subsidiaries or divisions thereof, may represent potential buyers of businesses through its mergers and acquisition activities and may provide lending and other related financing services in
connection with such transactions. Morgan Stanley’s compensation for such activities is usually based upon realized consideration and is usually contingent, in substantial part, upon the closing of the transaction. Under these circumstances,
the Fund may be precluded from participating in a transaction with or relating to the company being sold or participating in any financing activity related to merger or acquisition.

The involvement or presence of Morgan Stanley in the investment
banking and other commercial activities described above (or the financial markets more broadly) may restrict or otherwise limit investment opportunities that may otherwise be available to the Fund. For example, issuers may hire and compensate Morgan
Stanley to provide underwriting, financial advisory, placement agency, brokerage services or other services and, because of limitations imposed by applicable law and regulation, the Fund may be prohibited from buying or selling securities issued by
those issuers or participating in related transactions or otherwise limited in its ability to engage in such investments.

In addition, in situations where the investment adviser is
required to aggregate its positions with those of other Morgan Stanley business units for position limit calculations, the investment adviser may have to refrain from making investments due to the positions held by other Morgan Stanley business
units or their clients. There may be other situations where the investment adviser refrains from making an investment or refrains from taking certain actions related to the management of such investment due to, among other reasons, additional
disclosure obligations, regulatory requirements, policies, and reputational risk, or the investment adviser may limit purchases or sales of securities in respect of which Morgan Stanley is engaged in an underwriting or other distribution
capacity.

Morgan Stanley’s Marketing Activities. Morgan Stanley is engaged in the business of underwriting, syndicating, brokering, administering, servicing, arranging and advising on the distribution of a wide variety of securities and other investments in which the
Fund may invest. Subject to the restrictions of the 1940 Act, including Sections 10(f) and 17(e) thereof, the Fund may invest in transactions in which Morgan Stanley acts as underwriter, placement

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Potential Conflicts of
Interest — continued

agent, syndicator,
broker, administrative agent, servicer, advisor, arranger or structuring agent and receives fees or other compensation from the sponsors of such products or securities. Any fees earned by Morgan Stanley in such capacity will not be shared with the
investment adviser or the Fund. Certain conflicts of interest, in addition to the receipt of fees or other compensation, would be inherent in these transactions. Moreover, the interests of one of Morgan Stanley’s clients with respect to an
issuer of securities in which the Fund has an investment may be adverse to the investment adviser’s or the Fund’s best interests. In conducting the foregoing activities, Morgan Stanley will be acting for its other clients and will have
no obligation to act in the investment adviser’s or the Fund’s best interests. Due to the restrictions of the 1940 Act, the Fund may be restricted from participating in certain transactions in which Morgan Stanley acts as underwriter,
placement agent, syndicator, broker, administrative agent, servicer, advisor, arranger or structuring agent, including transactions that would otherwise be beneficial to the Fund.

Client Relationships. Morgan
Stanley has existing and potential relationships with a significant number of corporations, institutions and individuals. In providing services to its clients, Morgan Stanley may face conflicts of interest with respect to activities recommended to
or performed for such clients, on the one hand, and the Fund, its shareholders or the entities in which the Fund invests, on the other hand. In addition, these client relationships may present conflicts of interest in determining whether to offer
certain investment opportunities to the Fund.

In
acting as principal or in providing advisory and other services to its other clients, Morgan Stanley may engage in or recommend activities with respect to a particular matter that conflict with or are different from activities engaged in or
recommended by the investment adviser on the Fund’s behalf.

Principal Investments. There
may be situations in which the Fund’s interests may conflict with the interests of one or more general accounts of Morgan Stanley and its affiliates or accounts managed by Morgan Stanley or its affiliates. This may occur because these accounts
hold public and private debt and equity securities of many issuers which may be or become portfolio companies, or from whom portfolio companies may be acquired.

Transactions with Portfolio Companies of Affiliated Investment
Accounts. The companies in which the Fund may invest may be counterparties to or participants in agreements, transactions or other arrangements with portfolio companies or other entities of portfolio investments of
Affiliated Investment Accounts (for example, a company in which the Fund invests may retain a company in which an Affiliated Investment Account invests to provide services or may acquire an asset from such company or vice versa). Certain of these
agreements, transactions and arrangements involve fees, servicing payments, rebates and/or other benefits to Morgan Stanley or its affiliates. For example, portfolio entities may, including at the encouragement of Morgan Stanley, enter into
agreements regarding group procurement and/or vendor discounts. Morgan Stanley and its affiliates may also participate in these agreements and may realize better pricing or discounts as a result of the participation of portfolio entities. To the
extent permitted by applicable law, certain of these agreements may provide for commissions or similar payments and/or discounts or rebates to be paid to a portfolio entity of an Affiliated Investment Account, and such payments or discounts or
rebates may also be made directly to Morgan Stanley or its affiliates. Under these arrangements, a particular portfolio company or other entity may benefit to a greater degree than the other participants, and the Morgan Stanley Funds, investment
vehicles and accounts (which may or may not include the Fund) that own an interest in such entity will receive a greater relative benefit from the arrangements than the Morgan Stanley Funds, investment vehicles or accounts that do not own an
interest therein. Fees and compensation received by portfolio companies of Affiliated Investment Accounts in relation to the foregoing will not be shared with a Fund or offset advisory fees payable.

Investments in Portfolio Investments of Other Funds. To the extent permitted by applicable law, when the Fund invests in certain companies or other entities, other funds affiliated with the investment adviser may have made or may be making an investment in such companies
or other entities. Other funds that have been or may be managed by the investment adviser may invest in the companies or other entities in which the Fund has made an investment. Under such circumstances, the Fund and such other funds may have
conflicts of interest (e.g., over the terms, exit strategies and related matters, including the exercise of remedies of their respective investments). If the interests held by the Fund are different from (or take priority over) those held by such
other funds, the investment adviser may be required to make a selection at the time of conflicts between the interests held by such other funds and the interests held by the Fund.

Investments in Morgan Stanley Funds and Other Funds. To the extent permitted by applicable law, the Fund may invest in a fund affiliated with the investment adviser or its affiliates or a fund advised by the investment adviser or its affiliates. In connection with any
such investments, an investing Fund, to the extent permitted by the 1940 Act, will pay all advisory, administrative and/or Rule 12b-1 fees applicable to the investment. Investments by a Fund in a fund affiliated with the investment adviser or its
affiliates or a fund advised by the investment adviser or its affiliates present potential conflicts of interest, including potential incentives to invest in smaller or newer funds to increase asset levels or provide greater viability. The
investment adviser voluntarily waives advisory fees of a Fund associated with investments by the Fund in a fund advised by the investment adviser or its affiliates which will reduce, but will not eliminate, these types of conflicts.

The Affiliated Investment Accounts (including the Funds) may,
individually or in the aggregate, own a substantial percentage of a Fund. Further, the Adviser, its affiliates, or another entity (i.e., a seed investor) may invest in the Funds at or near the establishment of such Funds, which may facilitate the
Funds achieving a specified size or scale. The Adviser and/or its affiliates may make payments to an investor that contributes seed capital to a Fund. Such payments may continue for a specified period of time and/or until a specified dollar amount
is reached, and will be made from the assets of the Adviser and/or such affiliates (and not the applicable Fund). Seed investors may contribute all or a majority of the assets in a Fund. There is a risk that such seed investors may redeem their
investments in the Fund, particularly after payments from the Adviser and/or its affiliates have ceased. Such redemptions could negatively impact a Fund’s liquidity, expenses and market price of its shares, as applicable.

Allocation of Expenses.
Expenses may be incurred that are attributable to the Fund and one or more other Affiliated Investment Accounts (including in connection with issuers in which the Fund and such other Affiliated Investment Accounts have overlapping investments). The
allocation of such expenses

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Potential Conflicts of
Interest — continued

among such entities
raises potential conflicts of interest. The investment adviser and its affiliates intend to allocate such common expenses among the Fund and any such other Affiliated Investment Accounts on a pro rata basis or in such other manner as the investment
adviser deems to be fair and equitable or in such other manner as may be required by applicable law.

Temporary Investments. To more
efficiently invest short-term cash balances held by the Fund, the investment adviser may invest such balances on an overnight “sweep” basis in shares of one or more money market funds or other short-term vehicles. It is anticipated that
the investment adviser to these money market funds or other short-term vehicles may be the investment adviser (or an affiliate) to the extent permitted by applicable law, including Rule 12d1-1 under the 1940 Act. In such a case, the affiliated
investment adviser may receive asset-based fees in respect of the Fund’s investment (which will reduce the net return realized by the Fund).

Transactions with Affiliates.
The investment adviser and any investment sub-adviser might purchase securities from underwriters or placement agents in which a Morgan Stanley affiliate is a member of a syndicate or selling group, as a result of
which an affiliate might benefit from the purchase through receipt of a fee or otherwise. Neither the investment adviser nor any investment sub-adviser will purchase securities on behalf of the Fund from an affiliate that is acting as a manager of a
syndicate or selling group. Purchases by the investment adviser on behalf of the Fund from an affiliate acting as a placement agent must meet the requirements of applicable law. Furthermore, Morgan Stanley may face conflicts of interest when a Fund
uses service providers affiliated with Morgan Stanley because Morgan Stanley receives greater overall fees when they are used.

Affiliated Indexes. Affiliates
of the investment adviser develop, own and operate indexes (“Indexes”), and may continue to do so in the future, based on investment and trading strategies and concepts developed by the investment adviser or its affiliates
(“Adviser Strategies”). Some of the Funds seek to track the performance of the Indexes. The investment adviser manages Accounts which track the same Indexes used by the Funds or which are based on the same, or substantially similar,
Adviser Strategies that are used in the operation of the Indexes and the Funds. The operation of the Indexes, the Funds and the Accounts in this manner gives rise to potential conflicts of interest. For example, Accounts that track the same Indexes
used by the Funds may engage in purchases and sales of securities prior to when the Index and the Funds engage in similar transactions because such Accounts may be managed and rebalanced on an ongoing basis, whereas the Funds’ portfolios are
only rebalanced on a periodic or other basis subsequent to the rebalancing of the Index.

The investment adviser has adopted policies and procedures that
are designed to address potential conflicts that arise in connection with the operation of the Indexes, the Funds and the Accounts. The investment adviser has established certain information barriers and other policies designed to address the
sharing of information between different businesses within the investment adviser, including with respect to personnel responsible for constructing and maintaining the Indexes and those involved in decision-making for the Funds.

Valuation of the Fund’s Investments. The investment adviser performs certain valuation services related to securities and other assets held by the Fund and performs such services in accordance with its valuation policies. The investment adviser will face a
conflict with respect to valuation of the Fund’s investments generally because of the effect of such valuations on the investment adviser’s fees and other compensation and performance of the Fund.

Proxy Voting by the Adviser.
The investment adviser has implemented processes designed to prevent conflicts of interest from influencing proxy voting decisions that it makes on behalf of advisory clients, including the Funds, and to help ensure that such decisions are made in
accordance with its fiduciary obligations to its clients. Notwithstanding such proxy voting processes, proxy voting decisions made by the investment adviser in respect of securities held by the Fund may benefit the interests of Morgan Stanley and/or
accounts other than the Fund. Further, the investment adviser may make different proxy voting decisions in respect of the same security held by clients with different investment objectives or strategies.

Potential Conflict of Interest Related to Use of Sub-Adviser(s). To the extent the Fund’s investment adviser engages affiliated and/or unaffiliated sub-advisers, the investment adviser generally expects to compensate the sub-adviser out of the advisory fee it receives from the
Fund, which creates an incentive for the investment adviser to select sub-adviser(s) with lower fee rates or to select affiliated sub-adviser(s). In addition, a sub-adviser may have interests and relationships that create actual or potential
conflicts of interest related to their management of Fund assets allocated to or managed by the sub-adviser. These conflicts may be similar to or different from the conflicts described herein related to Morgan Stanley and its investment advisory
affiliates. For additional information about potential conflicts of interest for each sub-adviser(s) can be found in the relevant sub-adviser’s Form ADV. A copy of Part 1 and Part 2 of a sub-adviser’s Form ADV is available on the
SEC’s website (www.adviserinfo.sec.gov).

Electronic Communication Networks and Alternative Trading
Systems. The investment adviser’s affiliate(s) have ownership interests in and/or board seats on electronic communication networks (“ECNs”) or other alternative trading systems
(“ATSs”). In certain instances the investment adviser’s affiliate(s) could be deemed to control one or more of such ECNs or ATSs based on the level of such ownership interests and whether such affiliates are represented on the
board of such ECNs or ATSs. Consistent with its fiduciary obligation to seek best execution, the Adviser may, from time to time, directly or indirectly, effect client trades through ECNs or other ATSs in which the Firm’s affiliates have or
could acquire an interest or board seat. These affiliates might receive an indirect economic benefit based upon their ownership in the ECNs or other ATSs. The investment adviser will, directly or indirectly, execute through an ECN or other ATSs in
which an affiliate has an interest only in situations where the Firm or the broker dealer through whom it is accessing the ECN or ATS reasonably believes such transaction will be in the best interest of its clients and the requirements of applicable
law have been satisfied.

General Process for
Potential Conflicts. All of the transactions described above involve the potential for conflicts of interest between the investment adviser, related persons of the investment adviser and/or their clients. The
Advisers Act, the 1940 Act and ERISA impose certain requirements designed to decrease the possibility of conflicts of interest between an investment adviser and its clients. In some cases, transactions may be permitted subject to fulfillment of
certain conditions. Certain other transactions may be prohibited. In addition, the investment adviser has instituted policies and procedures designed to

Eaton Vance

National Municipal Opportunities Trust

March 31, 2026

Potential Conflicts of
Interest — continued

prevent conflicts of
interest from arising and, when they do arise, to ensure that it effects transactions for clients in a manner that is consistent with its fiduciary duty to its clients and in accordance with applicable law. The investment adviser seeks to ensure
that potential or actual conflicts of interest are appropriately resolved taking into consideration the overriding best interests of the client.

Delivery of Shareholder Documents. The Securities and Exchange Commission (SEC) permits funds to deliver only one copy of shareholder documents, including prospectuses, proxy statements and
shareholder reports, to fund investors with multiple accounts at the same residential or post office box address. This practice is often called “householding” and it helps eliminate duplicate mailings to shareholders. Equiniti Trust Company, LLC (“EQ”), the closed-end funds transfer agent, or your financial intermediary, may household the mailing of your documents
indefinitely unless you instruct EQ, or your financial intermediary, otherwise. If you would prefer that your Eaton Vance documents not be householded, please contact EQ or your financial
intermediary. Your instructions that householding not apply to delivery of your Eaton Vance documents will typically be effective within 30 days of receipt by EQ or your financial intermediary.

Portfolio
Holdings. Each Eaton Vance Fund and its underlying Portfolio(s) (if applicable) files a schedule of portfolio holdings on Part F to Form N-PORT with the
SEC. Certain information filed on Form N-PORT may be viewed on the Eaton Vance website at www.eatonvance.com, by calling Eaton Vance at 1-800-262-1122 or in the EDGAR database on the SEC’s website at www.sec.gov.

Proxy
Voting. From time to time, funds are required to vote proxies related to the securities held by the funds. The Eaton Vance Funds or their underlying
Portfolios (if applicable) vote proxies according to a set of policies and procedures approved by the Funds’ and Portfolios’ Boards. You may obtain a description of these policies and procedures and information on how the Funds or
Portfolios voted proxies relating to portfolio securities during the most recent 12-month period ended June 30, without charge, upon request, by calling 1-800-262-1122 and by accessing the SEC’s website at www.sec.gov. You may also access
proxy voting information for the Eaton Vance Funds or their underlying Portfolios at www.eatonvance.com/
proxyvoting.

Share Repurchase
Program. The Fund’s Board of Trustees has approved a share repurchase program authorizing the Fund to repurchase up to 10% of its common shares
outstanding as of the last day of the prior calendar year in open-market transactions at a discount to net asset value. The repurchase program does not obligate the Fund to purchase a specific amount of shares. The Fund’s repurchase activity,
including the number of shares purchased, average price and average discount to net asset value, is disclosed in the Fund’s annual and semi-annual reports to shareholders.

Additional Notice to Shareholders. If applicable, a Fund may also redeem or purchase its outstanding preferred shares in order to maintain compliance with regulatory requirements, borrowing or
rating agency requirements or for other purposes as it deems appropriate or necessary.

Closed-End Fund Information. Eaton Vance closed-end funds make fund performance data and certain information about portfolio characteristics available on the Eaton Vance website shortly
after the end of each month. Other information about the funds is available on the website. The funds’ net asset value per share is readily accessible on the Eaton Vance website. Portfolio holdings for the most recent month-end are also posted
to the website approximately 30 days following the end of the month. This information is available at www.eatonvance.com on the fund information pages under “Closed-End Funds & Term Trusts.”

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Investment Adviser and Administrator

Eaton Vance Management
One Post Office Square
Boston, MA 02109

Custodian

State Street Bank and Trust Company
One Congress Street, Suite 1
Boston, MA 02114-2016

Transfer Agent

Equiniti Trust Company, LLC (“EQ”)
P.O. Box 500
Newark, NJ 07101

Independent Registered Public Accounting Firm

Deloitte & Touche LLP
115 Federal Street, Suite 15
Boston, MA 02110-1894

Fund Offices

One Post Office Square
Boston, MA 02109