Cover	Apr. 08, 2022
Document Type	8-K
Amendment Flag	false
Document Period End Date	Apr. 08, 2022
Entity File Number	001-39818
Entity Registrant Name	INSU ACQUISITION CORP. III
Entity Central Index Key	0001829889
Entity Tax Identification Number	85-3356658
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	2929 Arch Street
Entity Address, Address Line Two	Suite 1703
Entity Address, City or Town	Philadelphia
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	19104
City Area Code	(215)
Local Phone Number	701-9555
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 share of Class A common stock and one-third of one redeemable warrant
Title of 12(b) Security	Units, each consisting of one share of Class A common stock and one-third of one redeemable warrant
Trading Symbol	IIIIU
Security Exchange Name	NASDAQ
Class A common stock, par value $0.0001 per share
Title of 12(b) Security	Class A common stock, par value $0.0001 per share
Trading Symbol	IIII
Security Exchange Name	NASDAQ
Warrants, each whole warrant exercisable for one share of Class A common stock
Title of 12(b) Security	Warrants, each whole warrant exercisable for one share of Class A common stock
Trading Symbol	IIIIW
Security Exchange Name	NASDAQ