v3.26.1

Cover - shares	3 Months Ended
Cover - shares	Feb. 28, 2026	Apr. 23, 2026
Document Type	10-Q
Amendment Flag	false
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Feb. 28, 2026
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2026
Current Fiscal Year End Date	--11-30
Entity File Number	001-42555
Entity Registrant Name	Quartzsea Acquisition Corporation
Entity Central Index Key	0002047455
Entity Tax Identification Number	00-0000000
Entity Incorporation, State or Country Code	E9
Entity Address, Address Line One	1185 Avenue of the Americas
Entity Address, Address Line Two	Suite 304
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10036
City Area Code	(212)
Local Phone Number	612-1400
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Elected Not To Use the Extended Transition Period	false
Entity Shell Company	true
Entity Common Stock, Shares Outstanding		11,409,900
Units, each consisting of one ordinary share and one right
Title of 12(b) Security	Units, each consisting of one ordinary share and one right
Trading Symbol	QSEAU
Security Exchange Name	NASDAQ
Ordinary shares, par value $0.0001 per share
Title of 12(b) Security	Ordinary Shares, par value $0.0001 per share
Trading Symbol	QSEA
Security Exchange Name	NASDAQ
Rights, each right entitling the holder to receive one-fifth of one ordinary share
Title of 12(b) Security	Rights, each right entitling the holder to receive one-fifth of one ordinary share
Trading Symbol	QSEAR
Security Exchange Name	NASDAQ

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Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.

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Local phone number for entity.

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Quartzsea Acquisition Corp 10-Q