Supplemental Prospectus (Form 424B3)

Filed pursuant to Rule 424(b)(3)

SEC File No. 333-282862

PROSPECTUS SUPPLEMENT NO. 9

(To Prospectus dated May 14, 2025)

PHOENIX ENERGY ONE, LLC

This prospectus supplement updates, amends, and supplements the prospectus, dated May 14, 2025 (as updated, amended, and supplemented to date, the "Prospectus"), which forms a part of our Registration Statement on Form S-1 (Registration No. 333-282862). Capitalized terms used in this prospectus supplement and not otherwise defined herein have the meanings specified in the Prospectus.

This prospectus supplement is being filed to update, amend, and supplement the information included in the Prospectus with the information contained in our Current Report on Form 8-K filed with the SEC on November 5, 2025, which is set forth below.

This prospectus supplement is not complete without the Prospectus. This prospectus supplement should be read in conjunction with the Prospectus, which is to be delivered with this prospectus supplement, and is qualified by reference thereto, except to the extent that the information in this prospectus supplement updates or supersedes the information contained in the Prospectus. Please keep this prospectus supplement with your Prospectus for future reference.

Investing in the Notes involves risks. See "Risk Factors" beginning on page 19 of the Prospectus.

Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplement or the accompanying Prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is November 6, 2025.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): November 3, 2025

Phoenix Energy One, LLC

(Exact name of registrant as specified in its charter)

Registrant's telephone number, including area code: (949) 416-5037

Not Applicable

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

On November 3, 2025, Brandon Allen, Chief Operating Officer of Phoenix Energy One, LLC (the "Company") notified the Company of his intent to resign immediately. Mr. Allen's resignation is not a result of any disagreement with the Company on any matter relating to the Company's operations, policies or practices.

On November 3, 2025, the Company appointed David Scadden as the Company's Chief Operating Officer, effective immediately. Previously, Mr. Scadden, age 35, served as the Company's Chief Execution Officer since September 2024 and, before that, VP of Drilling and Completions of the Company's wholly owned subsidiary, Phoenix Operating LLC ("PhoenixOp"), beginning in February 2023. Before joining PhoenixOp, Mr. Scadden spent several years accumulating operational oil & gas experience throughout the American West, most recently serving as the Lead Drilling Engineer and Superintendent at Chord Energy from March 2021 to December 2022 and the Senior Drilling Engineer and Superintendent at Chord Energy prior to that. Mr. Scadden has served in roles spanning from onsite supervision to engineering management and has contributed to drilling projects in the San Juan Basin, Piceance Basin, Denver-Julesburg Basin, Eagle Ford Group, Granite Wash, and Williston Basin.

The Company has not entered into or amended any compensatory agreement or arrangement with Mr. Scadden in connection with his appointment as Chief Operating Officer, and no grants or other material benefits have been provided to Mr. Scadden in connection with his appointment.

There is no arrangement or understanding between Mr. Scadden and any other person pursuant to which he was appointed as an officer of the Company. Mr. Scadden has no family relationships with any of the Company's directors or executive officers. There are no transactions involving the Company and Mr. Scadden that the Company would be required to be disclosed pursuant to Item 404(a) of Regulation S-K.

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 hereunto duly authorized.

Dated: November 5, 2025