| Cover | Oct. 21, 2024 |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Oct. 21, 2024 |
| Entity File Number | 001-42138 |
| Entity Registrant Name | FLAG SHIP ACQUISITION CORPORATION |
| Entity Central Index Key | 0001850059 |
| Entity Tax Identification Number | 00-0000000 |
| Entity Incorporation, State or Country Code | E9 |
| Entity Address, Address Line One | 26 Broadway |
| Entity Address, Address Line Two | Suite 934 |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10004 |
| City Area Code | (646) |
| Local Phone Number | 362-0256 |
| Written Communications | true |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Elected Not To Use the Extended Transition Period | false |
| Units, each consisting of one Ordinary Share, $0.001 par value, and one right | |
| Title of 12(b) Security | Units, each consisting of one Ordinary Share, $0.001 par value, and one right |
| Trading Symbol | FSHPU |
| Security Exchange Name | NASDAQ |
| Ordinary Shares, $0.001 par value | |
| Title of 12(b) Security | Ordinary Shares, $0.001 par value |
| Trading Symbol | FSHP |
| Security Exchange Name | NASDAQ |
| Rights to receive one-tenth (1/10 | |
| Title of 12(b) Security | Rights to receive one-tenth (1/10th) of one Ordinary Share |
| Trading Symbol | FSHPR |
| Security Exchange Name | NASDAQ |
