v3.26.1
Document and Entity Information
Jun. 25, 2026
Document And Entity Information [Line Items]  
Amendment Flag false
Entity Central Index Key 0002080019
Document Type 8-K
Document Period End Date Jun. 25, 2026
Entity Registrant Name GigCapital8 Corp.
Entity Incorporation State Country Code E9
Entity File Number 001-42893
Entity Tax Identification Number 98-1868645
Entity Address, Address Line One 1731 Embarcadero Rd.
Entity Address, Address Line Two Suite 200
Entity Address, City or Town Palo Alto
Entity Address, State or Province CA
Entity Address, Postal Zip Code 94303
City Area Code 650
Local Phone Number 276-7040
Written Communications true
Soliciting Material false
Pre Commencement Tender Offer false
Pre Commencement Issuer Tender Offer false
Entity Emerging Growth Company true
Entity Ex Transition Period false
Capital Units [Member]  
Document And Entity Information [Line Items]  
Security 12b Title Units, each consisting of one Class A ordinary share, $0.0001 par value, and one right to receive one-fifth of one Class A ordinary share
Trading Symbol GIWWU
Security Exchange Name NASDAQ
Class A Ordinary Shares 0.0001 Par Value [Member]  
Document And Entity Information [Line Items]  
Security 12b Title Class A ordinary shares, $0.0001 par value
Trading Symbol GIW
Security Exchange Name NASDAQ
Rights One Right To Receive One Fifth Of One Class A Ordinary Share Each Five Rights Entitling The Holder Thereof To Receive One Class A Ordinary Share Upon The Consummation Of A Business Combination [Member]  
Document And Entity Information [Line Items]  
Security 12b Title Rights, one right to receive one-fifth of one Class A ordinary share, each five rights entitling the holder thereof to receive one Class A ordinary
Trading Symbol GIWWR
Security Exchange Name NASDAQ