| Document And Entity Information | Jan. 29, 2024 |
| Cover [Abstract] | |
| Document Type | 8-K/A |
| Amendment Flag | true |
| Document Period End Date | Jan. 29, 2024 |
| Entity Registrant Name | 5E ADVANCED MATERIALS, INC. |
| Entity Central Index Key | 0001888654 |
| Entity Emerging Growth Company | true |
| Entity File Number | 001-41279 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 87-3426517 |
| Entity Address, Address Line One | 9329 Mariposa Road, Suite 210 |
| Entity Address, City or Town | Hesperia |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 92344 |
| City Area Code | (442) |
| Local Phone Number | 221-0225 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Ex Transition Period | true |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | FEAM |
| Security Exchange Name | NASDAQ |
| Amendment Description | This Amendment No. 1 to the Current Report on Form 8-K amends Exhibit 4.1 of the Current Report on Form 8-K filed on January 29, 2024 (the “Original Form 8-K”) solely to correct a scrivener's error related to the total number of shares of the Company’s common stock, par value $0.01 (“Common Stock”) outstanding included in Exhibit 4.1 to the Original Form 8-K, and to update the date of such disclosures to February 2, 2024. No other changes have been made to the Original Form 8-K. |
