FORTUNA MINING CORP.

Foreign Filer Report • Nov 6, 2025

6-K 1 tmb-20250930x6k.htm 6-K Enhanced HTML document created with Toppan Merrill Bridge 11.1.0.82 Created on: 11/6/2025 09:33:31 AM (UTC)

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 November 2025

Commission File Number 001-35297

Fortuna Mining Corp.

(Translation of registrant’s name into English)

1111 Melville Street, Suite 820, Vancouver, British Columbia, Canada V6E 3V6

(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 þ

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.

Date: November 5, 2025 Fortuna Mining Corp. (Registrant) By: /s/ " Jorge Ganoza Durant " Jorge Ganoza Durant President and CEO

Exhibits:

​	​	​
99.1		Interim Financial Statements for the period ended September 30, 2025
99.2	​	Management’s Discussion and Analysis for the period ended September 30, 2025
99.3	​	CEO Certification
99.4	​	CFO Certification
99.5	​	News release dated November 5, 2025