SEC Form 6-K filed by Sayona Mining Limited

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 September 2025

Commission File Number 001-42819

SAYONA MINING LIMITED

(Translation of registrant’s name into English)

Level 28,

10 Eagle Street

Brisbane, Queensland 4000

Australia

(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   x                  Form 40-F   ¨

Sayona Mining Limited (the “Registrant”) is filing the following exhibits on this Report on Form 6-K, each of which is hereby incorporated by reference:

Exhibit

SIGNATURE

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.