Exhibit 4.27

AMENDMENT NO. 1 TO

AMENDED AND RESTATED

HEADS OF AGREEMENT

This Amendment (this “Amendment”), is made as of September 29^th, 2025, by and between Critical Metals Corp., a BVI business company incorporated in the British Virgin Islands (the “CRML” or the “Company”) and Rimbal Pty Ltd (a private Australian company) (“Vendor” and, together with the Company, the “Parties”). Defined terms used but not otherwise defined herein shall have the meanings given to such terms in the A&R HoA (as defined below).

WHEREAS, the Parties are parties to that certain Heads of Agreement, dated as of June 4, 2024, together with its addendum dated June 27, 2024 (the “HoA”), whereby the CRML agreed to acquire an up to a 92.5% interest in the Tanbreez Green Rare Earth Mine (the “Tanbreez Project”);

WHEREAS, the Parties are a party to that certain Amended and Restated Heads of Agreement, dated as of July 19, 2024, which amended and restated in full the HoA (the “A&R HoA”);

WHEREAS, the Vendor has as of the date of this Amendment requested the Greenlandic Mineral Resources Authority to grant the MLSA CoC Approval (as defined below), which approval remains pending; and

WHEREAS, the Parties desire to enter into this Amendment in order to amend the obligations under the A&R HoA.

NOW THEREFORE, for good and valuable consideration, the receipt of which is hereby acknowledged, the Parties hereto hereby agree as follows:

“(b) upon approval from the Greenlandic Mineral Resources Authority of the transfer of control in TAN, see clause 13 (MLSA CoC Approval), CRML shall acquire the remaining TAN Shares held by the Vendor, being 50.5% of TAN’s issued capital (Stage 2 Interest)”

“(b) for the Stage 2 interest, 14,500,000 CRML Shares (Deferred Consideration Shares, and together with the Upfront Consideration Shares, the Consideration Shares)”

“(a) Upon the MLSA CoC Approval, CRML shall acquire the Stage 2 Interest in exchange for the Deferred Consideration Shares. The acquisition shall be completed within 14 days from a written notice by the Vendor that the MLSA CoC Approval has been obtained, such notice to include reasonable supporting information and evidence to demonstrate that such approval has been obtained.

(b) Promptly following the MLSA CoC Approval and the provision of written notice from the Vendor, CRML shall: (i) provide a duly signed transfer form in respect of the Deferred Consideration Shares to the Vendor (or their nominees); (ii) deliver all other information, items and documents or things required by the Vendor for CRML to transfer ownership of the Deferred Consideration Shares acquired in exchange for the TAN Shares which the Vendor may reasonably require; and (iii) take all other steps required by CRML’s constituent documents and applicable laws to constitute and evidence the Vendor as the holder of the Deferred Consideration Shares acquired in exchange for the TAN Shares.

(c) Promptly following the MLSA CoC Approval and conditioned on CRML performing its obligations in (b) above, the Vendor must deliver to CRML:

(i) a separate instrument of transfer in registrable form for the TAN Shares acquired in exchange for the Deferred Consideration Shares in favour of CRML (as transferee) which have been duly executed by the Vendor (as transferor);

(ii) acceptance of the resignations of each of the directors and secretaries of TAN (as required by CRML) with effect from the date that CRML has performed its obligations in (b) above confirming that they each have no claim for loss of office or otherwise against TAN;

(iii) approval of the appointment as replacement directors and secretary of TAN of those persons nominated by CRML by written notice;

(iv) recording CRML as the holder of the TAN Shares acquired in exchange for the Deferred Consideration Shares in TAN’s shareholders’ register;

(v) for the Vendor’s part, the approval of the registration of the transfers of the TAN Shares acquired in exchange for the Deferred Consideration Shares;

(vi) all other information, items and documents or things required by CRML for the Vendor to transfer ownership of the TAN Shares acquired in exchange for the Deferred Consideration Shares which CRML may reasonably require; and

(vii) take all other steps required under TAN’s constituent documents and applicable laws to constitute and evidence CRML as the holder of the TAN Shares acquired in exchange for the Deferred Consideration Shares.

“(c) following the issuance of Deferred Consideration Shares, Vendor will be granted the right to appoint a nominee director to the board of CRML.”

THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR APPLICABLE STATE SECURITIES LAWS. THE SECURITIES MAY NOT BE OFFERED FOR SALE, SOLD, TRANSFERRED OR ASSIGNED (I) IN THE ABSENCE OF (A) AN EFFECTIVE REGISTRATION STATEMENT FOR THE SECURITIES UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR

(B) AN OPINION OF COUNSEL TO THE HOLDER (IF REQUESTED BY THE COMPANY), IN A FORM REASONABLY ACCEPTABLE TO THE COMPANY, THAT REGISTRATION IS NOT REQUIRED UNDER SAID ACT OR

(II) UNLESS SOLD OR ELIGIBLE TO BE SOLD PURSUANT TO RULE 144 OR RULE 144A UNDER SAID ACT.

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IN WITNESS WHEREOF, the Parties hereto have caused this Amendment to be duly executed by their respective authorized officer as of the date first above written.