Castor Maritime Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 20-F

OR

For the fiscal year ended December 31, 2025

OR

For the transition period from ________________________ to ________________________

OR

Date of event requiring this shell company report: Not applicable

Commission file number 001-38802

CASTOR MARITIME INC.

(Exact name of Registrant as specified in its charter)

N/A

(Translation of Registrant’s name into English)

Republic of the Marshall Islands

(Jurisdiction of incorporation or organization)

223 Christodoulou Chatzipavlou Street

Hawaii Royal Gardens

3036 Limassol, Cyprus

(Address of principal executive offices)

Petros Panagiotidis, Chairman, Chief Executive Officer and Chief Financial Officer 223 Christodoulou Chatzipavlou Street, Hawaii Royal Gardens, 3036 Limassol, CY Phone number: + 357 25 357 767 Fax Number: + 357 25 357 796

(Name, Telephone, E-mail and/or Facsimile number and Address of Company Contact Person)

Securities registered or to be registered pursuant to Section 12(b) of the Act:

Securities registered or to be registered pursuant to Section 12(g) of the Act: None

Securities for which there is a reporting obligation pursuant to Section 15(d) of the Act: None

Indicate the number of outstanding shares of each of the issuer’s classes of share capital as of the close of the period covered by the annual report:

As of December 31, 2025, there were outstanding 9,662,354 common shares of the Registrant, $0.001 par value per share.

Indicate by check mark if the Registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.

If this report is an annual report or transition report, indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934.

Indicate by check mark whether the Registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports) and (2) has been subject to such filing requirements for the past 90 days.

Indicate by check mark whether the Registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during this preceding 12 months (or for such shorter period that the registrant was required to submit such files).

Indicate by check mark whether the Registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or an emerging growth company. See definition of “large accelerated filer”, “accelerated filer,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company that prepares its financial statements in accordance with U.S. GAAP, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards† provided pursuant to Section 13(a) of the Exchange Act. ☐

† The term “new or revised financial accounting standard” refers to any update issued by the Financial Accounting Standards Board to its Accounting Standards Codification after April 5, 2012.

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report.☐

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements. ☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). ☐

Indicate by check mark which basis of accounting the Registrant has used to prepare the financial statements included in this filing:

If “Other” has been checked in response to the previous question, indicate by check mark which financial statement item the Registrant has elected to follow.

If this is an annual report, indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).

(APPLICABLE ONLY TO ISSUERS INVOLVED IN BANKRUPTCY PROCEEDINGS DURING THE PAST FIVE YEARS)

Indicate by check mark whether the registrant has filed all documents and reports required to be filed by Sections 12, 13 or 15(d) of the Securities Exchange Act of 1934 subsequent to the distribution of securities under a plan confirmed by a court.

TABLE OF CONTENTS

i

CERTAIN DEFINED TERMS

Unless the context otherwise requires, as of the date of and as used in this Annual Report, the terms:

We use the term “deadweight ton”, or “dwt”, in describing the size of dry bulk vessels. Dwt, expressed in metric tons (“mt”), each of which is equivalent to 1,000 kilograms, refers to the maximum weight of cargo and supplies that a vessel can carry. A “ton mile” is a standardized shipping metric and refers to the volume of cargo being carried (a “ton”) and the distance sailed for the shipment in nautical miles. We use the term “twenty foot equivalent unit” (“TEU”), the international standard measure of containers, in describing the capacity of our containerships.

ii

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

Matters discussed in this Annual Report on Form 20-F (the “Annual Report”) may constitute forward-looking statements. We intend such forward-looking statements to be covered by the safe harbor provisions for forward-looking statements contained in Section 27A of the Securities Act of 1933, as amended (the “Securities Act”) and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). Forward-looking statements include all matters that are not historical facts or matters of fact at the date of this document.

We are including this cautionary statement in connection with this safe harbor legislation. This Annual Report and any other written or oral statements made by us or on our behalf may include forward-looking statements, which reflect our current views with respect to future events and financial performance. These forward-looking statements may generally, but not always, be identified by the use of words such as “anticipate,” “believe,” “target,” “likely,” “will,” “would,” “could,” “should,” “seeks,” “continue,” “contemplate,” “possible,” “might,” “expect,” “intend,” “estimate,” “forecast,” “project,” “plan,” “objective,” “potential,” “may,” “anticipates” or similar expressions or phrases.

The forward-looking statements in this Annual Report are based upon various assumptions, including assumptions based on management’s examination of current or historical operating trends, data contained in our records and other data available from third parties. Although we believe that these assumptions were reasonable when made, because these assumptions are inherently subject to significant uncertainties and contingencies which are difficult or impossible to predict and are beyond our control, we cannot assure you that we will achieve or accomplish any forward-looking statements.

In addition to these assumptions, important factors that, in our view, could cause actual results to differ materially from those discussed in the forward-looking statements include generally:

iii

Any forward-looking statements contained herein are made only as of the date of this Annual Report, and we disclaim any intention or obligation to update any forward-looking statements as a result of developments occurring after the date of this Annual Report, except to the extent required by applicable law. New factors emerge from time to time, and it is not possible for us to predict all or any of these factors. Further, we cannot assess the impact of each such factor on our business or the extent to which any factor, or combination of factors, may cause actual results to be materially different from those contained in any forward-looking statement. See “Item 3. Key Information—D. Risk Factors” for a more detailed discussion of these risks and uncertainties and for other risks and uncertainties. Please see our filings with the Securities and Exchange Commission for a more complete discussion of these foregoing and other risks and uncertainties. These factors and the other risk factors described in this Annual Report are not necessarily all of the important factors that could cause actual results or developments to differ materially from those expressed in any of our forward-looking statements. Given these uncertainties, investors are cautioned not to place undue reliance on such forward-looking statements.

iv