| Cover | Aug. 13, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Aug. 13, 2021 |
| Entity File Number | 001-39991 |
| Entity Registrant Name | FIFTH WALL ACQUISITION CORP. I |
| Entity Central Index Key | 0001837014 |
| Entity Tax Identification Number | 85-4218526 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 600 Center Drive |
| Entity Address, Address Line Two | 10th Floor |
| Entity Address, City or Town | Los Angeles |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 90045 |
| City Area Code | 310 |
| Local Phone Number | 858-8878 |
| Written Communications | true |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Class A Common Stock, par value $0.0001 per share |
| Trading Symbol | FWAA |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Elected Not To Use the Extended Transition Period | false |
