Exhibit 99.1

5E Advanced Materials to Hold Stockholder Call

December 19, 2023

Company will provide an update on corporate matters, operations and the recently announced restructuring support agreement and financing package

HESPERIA, CA., December 12, 2023 (GLOBE NEWSWIRE) – 5E Advanced Materials, Inc. (Nasdaq: FEAM) (ASX: 5EA) (“5E” or the “Company”), a boron and lithium company with U.S. government Critical Infrastructure designation for its 5E Boron Americas Complex, today announced that it will hold a conference call for shareholders and analysts on Tuesday, December 19, 2023 at 5:00pm EST (9:00am Sydney) to discuss recent company developments, operational updates and the Company’s recently announced restructuring support agreement and financing package (the “Transaction”). The call will be delivered by Susan Brennan, Chief Executive Officer and Paul Weibel, Chief Financial Officer of 5E Advanced Materials, Inc.

Investors, analysts and members of the media interested in listening to the live presentation are encouraged to join a webcast of the call, available at https://www.webcast-eqs.com/FEAM20231214. For those participants wishing to dial into the call, a participant dial-in is also available at: Dial-In: 877-407-0989 / +1 201-389-0921. A replay of the webcast will be available on the Company’s Investor Relations section of its website.

Contingency Considerations

The Company expects to implement the Transaction and restructuring through an out-of-court restructuring. If the conditions precedent to the out-of-court restructuring cannot be timely satisfied, including approval by the Company’s stockholders of certain proposals, the Company expects to implement the restructuring through bankruptcy in a pre-packaged Chapter 11 plan. The Company believes that completing the out-of-court restructuring will allow it to avoid possible disruptions of the business, preserve valuable capital and avoid additional expenses, and other uncertainties that would result from commencing the bankruptcy cases to effectuate the pre-packaged Chapter 11 plan.

No Offer or Solicitation

This document is for information purposes only, and is not intended to and does not constitute an offer to sell or the solicitation of an offer to subscribe for or buy or an invitation to purchase or subscribe for any securities or the solicitation of a proxy, consent, or authorization in any jurisdiction or any vote or approval in any jurisdiction pursuant to the Transaction or otherwise, nor shall there be any sale, issuance or transfer of securities in any jurisdiction in contravention of applicable law. No offering of securities shall be made except by means of a prospectus in accordance with the requirements of Section 10 of the Securities Act of 1933, as amended or an exemption therefrom.

Additional Information and Where to Find It

This communication may be deemed to be solicitation material in respect of the Transactions and certain stockholder approvals required thereby. In connection with the Transaction, the Company has filed a preliminary proxy statement on Schedule 14A with the Securities and

Exhibit 99.1

Exchange Commission (the “SEC”) and intends to file other relevant materials with the SEC, including a proxy statement in definitive form. Following the filing of the definitive proxy statement with the SEC, the Company will mail the definitive proxy statement and a proxy card to each stockholder entitled to vote at the special meeting relating to the Transaction. INVESTORS AND SECURITY HOLDERS OF THE COMPANY ARE URGED TO READ CAREFULLY AND IN THEIR ENTIRITY ALL RELEVANT DOCUMENTS (INCLUDING ANY AMENDMENTS OR SUPPLEMENTS THERETO) FILED WITH THE SEC, INCLUDING THE COMPANY’S PROXY STATEMENT, WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE COMPANY AND THE TRANSACTION. Copies of the proxy statement and other relevant materials and any other documents filed by the Company with the SEC may be obtained free of charge at the SEC’s website, at www.sec.gov. In addition, stockholders may obtain free copies of the proxy statement and other relevant materials by directing a request to: 5E Advanced Materials, Inc., 9329 Mariposa Road, Suite 210, Hesperia, CA 92344.

Participants in Proxy Solicitation

The Company and its directors and executive officers and other members of management and employees may be deemed to be participants in the solicitation of proxies from the Company’s stockholders in respect of the Transaction. Information about the directors and executive officers of the Company is set forth in its Annual Report on Form 10-K/A filed with the SEC on October 27, 2023 and the proxy statement filed with the SEC in connection with the Transaction. Other information regarding the persons who may be deemed participants in the proxy solicitations in connection with the Transaction, and a description of any interests that they have in the Transaction, by security holdings or otherwise, will be contained in the definitive proxy statement and other relevant materials to be filed with the SEC regarding the Transaction when they become available. Stockholders, potential investors, and other interested persons should read the definitive proxy statement carefully when it becomes available before making any voting or investment decisions. You may obtain free copies of these documents from the sources indicated above.

About 5E Advanced Materials, Inc.

5E Advanced Materials, Inc. (Nasdaq: FEAM) (ASX: 5EA) is focused on becoming a vertically integrated global leader and supplier of boron specialty and advanced materials, complemented by lithium co-product production. The Company’s mission is to become a supplier of these critical materials to industries addressing global decarbonization, food and domestic security. Boron and lithium products will target applications in the fields of electric transportation, clean energy infrastructure, such as solar and wind power, fertilizers, and domestic security. The business strategy and objectives are to develop capabilities ranging from upstream extraction and product sales of boric acid, lithium carbonate and potentially other co-products, to downstream boron advanced material processing and development. The business is based on our large domestic boron and lithium resource, which is located in Southern California and designated as Critical Infrastructure by the Department of Homeland Security’s Cybersecurity and Infrastructure Security Agency.

Forward-Looking Statements

This press release includes “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, as amended. All statements other than statements of historical fact included in this press release regarding our business strategy, plans, goal, and objectives are forward-looking statements. When used in this press release, the words “believe,” “project,” “expect,” “anticipate,” “estimate,” “intend,” “budget,” “target,” “aim,”

Exhibit 99.1

“strategy,” “estimate,” “plan,” “guidance,” “outlook,” “intent,” “may,” “should,” “could,” “will,” “would,” “will be,” “will continue,” “will likely result,” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain such identifying words. These forward-looking statements are based on 5E’s current expectations and assumptions about future events and are based on currently available information as to the outcome and timing of future events. We caution you that these forward-looking statements are subject to all of the risks and uncertainties, most of which are difficult to predict and many of which are beyond our control, incident to the extraction of the critical materials we intend to produce and advanced materials production and development. These risks include, but are not limited to: our limited operating history in the borates and lithium industries and no revenue from our proposed extraction operations at our properties; our need for substantial additional financing to execute our business plan and our ability to access capital and the financial markets; our status as an exploration stage company dependent on a single project with no known Regulation S-K 1300 mineral reserves and the inherent uncertainty in estimates of mineral resources; our lack of history in mineral production and the significant risks associated with achieving our business strategies, including our downstream processing ambitions; our incurrence of significant net operating losses to date and plans to incur continued losses for the foreseeable future; risks and uncertainties relating to the development of the Fort Cady project, including our ability to timely and successfully complete our Small Scale Boron Facility; our ability to obtain stockholder approval for and successfully implement the Transaction and related matters on a timely manner or at all; the implementation of and expected benefits from certain reduced spending measures, and other risks and uncertainties set forth in our filings with the U.S. Securities and Exchange Commission from time to time. Should one or more of these risks or uncertainties occur, or should underlying assumptions prove incorrect, our actual results and plans could differ materially from those expressed in any forward-looking statements. No representation or warranty (express or implied) is made as to, and no reliance should be place on, any information, including projections, estimates, targets, and opinions contained herein, and no liability whatsoever is accepted as to any errors, omissions, or misstatements contained herein. You are cautioned not to place undue reliance on any forward-looking statements, which speak only as to the date of this press release.

For additional information regarding these various factors, you should carefully review the risk factors and other disclosures in the Company’s Form 10-K filed on August 30, 2023. Additional risks are also disclosed by 5E in its filings with the U.S. Securities and Exchange Commission throughout the year, including its Form 10-K, Form 10-Qs and Form 8-Ks, as well as in its filings under the Australian Securities Exchange. Any forward-looking statements are given only as of the date hereof. Except as required by law, 5E expressly disclaims any obligation to update or revise any such forward-looking statements. Additionally, 5E undertakes no obligation to comment on third party analyses or statements regarding 5E’s actual or expected financial or operating results or its securities.

For further information contact:

Davis Snyder or Joseph Caminiti Alpha IR Group FEAM@alpha-ir.com Ph: +1 (312) 445-2870 J.T. Starzecki Chief Marketing Officer jstarzecki@5eadvancedmaterials.com Ph: +1 (612) 719-5076