UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13A-16 OR 15D-16 OF

THE SECURITIES EXCHANGE ACT OF 1934

For the month of July 2025

Commission File Number: 001-38802

CASTOR MARITIME INC.

(Translation of registrant’s name into English)

223 Christodoulou Chatzipavlou Street, Hawaii Royal Gardens, 3036 Limassol, Cyprus

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F ☒

Form 40-F ☐

INFORMATION CONTAINED IN THIS FORM 6-K REPORT

Attached to this report on Form 6-K as Exhibit 99.1 is a copy of the press release issued by Castor Maritime Inc. (the “Company”) on July 30, 2025 announcing the Company’s completion of a sale and leaseback transaction of the M/V Magic Thunder.

The information contained in this report on Form 6-K and Exhibit 99.1 attached hereto are hereby incorporated by reference into the Company’s registration statements on Form F-3 (File Nos. 333-236331, 333-240262 and 333-254977).

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

	CASTOR MARITIME INC.
Dated: July 30, 2025
	By:	/s/ Petros Panagiotidis
		Petros Panagiotidis
		Chairman, Chief Executive Officer and
		Chief Financial Officer

Castor Maritime Inc. 6-K