Cover	May 15, 2026
Document Type	8-K
Amendment Flag	false
Document Period End Date	May 15, 2026
Entity File Number	001-42472
Entity Registrant Name	PLUM ACQUISITION CORP. IV
Entity Central Index Key	0002030482
Entity Tax Identification Number	98-1795710
Entity Incorporation, State or Country Code	E9
Entity Address, Address Line One	2021 Fillmore St. #2089
Entity Address, City or Town	San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94115
City Area Code	929
Local Phone Number	529-7125
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 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	PLMKU
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	PLMK
Security Exchange Name	NASDAQ
Warrants included as part of the units, each whole warrant exercisable for one Class A ordinary share at an exercise price of $11.50
Title of 12(b) Security	Warrants included as part of the units, each whole warrant exercisable for one Class A ordinary share at an exercise price of $11.50
Trading Symbol	PLMKW
Security Exchange Name	NASDAQ