v3.26.1
Cover
Mar. 23, 2026
Document Type 8-K
Amendment Flag false
Document Period End Date Mar. 23, 2026
Entity File Number 001-43204
Entity Registrant Name Blue Water Acquisition Corp. IV
Entity Central Index Key 0002082847
Entity Tax Identification Number 00-0000000
Entity Incorporation, State or Country Code E9
Entity Address, Address Line One 15 E. Putnam Avenue
Entity Address, Address Line Two Suite 363
Entity Address, City or Town Greenwich
Entity Address, State or Province CT
Entity Address, Postal Zip Code 06830
City Area Code (203)
Local Phone Number 489-2110
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
Units, each consisting of one Class A ordinary share and one-half of one redeemable warrant  
Title of 12(b) Security Units, each consisting of one Class A ordinary share and one-half of one redeemable warrant
Trading Symbol BWIV.U
Security Exchange Name NYSE
Class A ordinary shares, par value $0.0001 per share  
Title of 12(b) Security Class A ordinary shares, par value $0.0001 per share
Trading Symbol BWIV
Security Exchange Name NYSE
Warrants, each whole warrant exercisable for one Class A ordinary share  
Title of 12(b) Security Warrants, each whole warrant exercisable for one Class A ordinary share
Trading Symbol BWIV.WS
Security Exchange Name NYSE