| Cover | Oct. 31, 2024 |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Oct. 31, 2024 |
| Entity File Number | 001-14050 |
| Entity Registrant Name | BLOCKCHAIN COINVESTORS ACQUISITION CORP. I |
| Entity Central Index Key | 0001873441 |
| Entity Tax Identification Number | 98-1607883 |
| Entity Incorporation, State or Country Code | E9 |
| Entity Address, Address Line One | PO Box 1093 |
| Entity Address, Address Line Two | Boundary Hall |
| Entity Address, Address Line Three | Cricket Square |
| Entity Address, City or Town | Grand Cayman |
| Entity Address, Country | KY |
| Entity Address, Postal Zip Code | KY1-1102 |
| City Area Code | (345) |
| Local Phone Number | 814-5726 |
| Written Communications | false |
| 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 |
| Entity Information, Former Legal or Registered Name | Not Applicable |
| Units, each consisting of one Class A ordinary share, par value $0.0001 per share, and one-half of one Redeemable Warrant | |
| Title of 12(b) Security | Units, each consisting of one Class A ordinary share, par value $0.0001 per share, and one-half of one Redeemable Warrant |
| Trading Symbol | BCSAU |
| Security Exchange Name | NASDAQ |
| Class A ordinary shares, par value $0.0001 per share, included as part of the Units | |
| Title of 12(b) Security | Class A ordinary shares, par value $0.0001 per share, included as part of the Units |
| Trading Symbol | BCSA |
| Security Exchange Name | NASDAQ |
| Redeemable Warrants included as part of the Units | |
| Title of 12(b) Security | Redeemable Warrants included as part of the Units |
| Trading Symbol | BCSAW |
| Security Exchange Name | NASDAQ |
