Filed Pursuant to Rule 424(b)(3)
Registration No. 333-290206

PROSPECTUS SUPPLEMENT NO. 6

(to Prospectus dated September 22, 2025)

Icon Energy Corp.

This prospectus supplement is being filed to update, amend and supplement the information contained in the prospectus dated September 22, 2025 (as supplemented or amended from time to time, the “Prospectus”), which forms a part of our Registration Statement on Form F-1 (Registration Statement No. 333-290206), with the information contained in our report on Form 6-K filed with the Securities and Exchange Commission on February 18, 2026.

The Prospectus relates to the sale from time to time of up to 2,071,442 common shares, par value $0.001 per share (“Common Shares”) of Icon Energy Corp., incorporated under the laws of the Marshall Islands, by YA II PN, Ltd., a Cayman Islands exempt limited company.

This prospectus supplement updates, amends and supplements the information in the Prospectus and is not complete without, and may not be delivered or utilized except in combination with, the Prospectus, including any amendments or supplements thereto. This prospectus supplement should be read in conjunction with the Prospectus and if there is any inconsistency between the information in the Prospectus and this prospectus supplement, you should rely on the information in this prospectus supplement.

Our Common Shares are currently listed on The Nasdaq Capital Market under the symbol “ICON.” On February 17, 2026, the last reported sales price of our Common Shares was $1.52 per share.

Effective January 8, 2026, the Company amended its Articles of Incorporation filed with the Registrar of Corporations of the Republic of the Marshall Islands to effect a 1-for-5 reverse stock split of the Company’s common stock (the “Reverse Split”). Unless otherwise noted, the share and per share information in this Prospectus Supplement No. 6 have been adjusted to give effect to the Reverse Split.

Investing in our securities involves a high degree of risk. You should carefully review the risks and uncertainties described in the section titled “Risk Factors” beginning on page 6 of the Prospectus, and under similar headings in any amendments or supplements to the Prospectus.

Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if the Prospectus or this prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is February 18, 2026.

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

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of February 2026

Commission File Number: 001-42174

Icon Energy Corp.

(Translation of registrant’s name into English)

c/o Pavimar Shipping Co.

17th km National Road

Athens-Lamia & Foinikos Str.

14564, Nea Kifissia

Athens, Greece

+30 211 88 81 300

(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

On February 16, 2026, Icon Energy Corp. (the “Company”) held its 2026 Annual Meeting of Shareholders (the “Annual Meeting”). At the Annual Meeting, the following three proposals, which are set forth in more detail in the Company’s Notice of Annual Meeting of Shareholders and Proxy Statement filed with the U.S. Securities and Exchange Commission and mailed to shareholders on or about January 29, 2026, were approved and adopted:

the election of Evangelos Macris as a Class II Director to serve until the 2029 Annual Meeting of Shareholders;

the ratification of the appointment of Ernst & Young (Hellas) Certified Auditors Accountants S.A. as the Company’s independent auditors for the fiscal year ending December 31, 2026; and

the approval of amendments to the Company’s Amended and Restated Articles of Incorporation (“AOI”) and Amended and Restated Bylaws (“Bylaws”), to (i) allow for the shares of the Company as per its authorized capital stock to be represented solely in uncertificated form or in any manner required by the rules of the stock exchange on which such shares may be listed, (ii) allow for shareholders’ written consent in lieu of a meeting unless otherwise required by law and subject to other specific provisions therein, and (iii) incorporate any amendments previously made, and to authorize the Company’s board of directors (the “Board”) to implement such amendments by filing an application to amend and restate the AOI with the Registrar of Corporations of the Republic of the Marshall Islands at any time following such approval.

This report on Form 6-K is hereby incorporated by reference into the Company’s registration statement on Form F-3 (File No. 333-291988), and shall be a part thereof, to the extent not superseded by documents or reports subsequently filed or furnished.

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.

	ICON ENERGY CORP.

Date: February 18, 2026	By:	/s/ Dennis Psachos
	Name:	Dennis Psachos
	Title:	Chief Financial Officer