Cover Page - shares	9 Months Ended
Cover Page - shares	Sep. 30, 2025	Nov. 13, 2025
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes
Amendment Flag	false
Document Period End Date	Sep. 30, 2025
Document Fiscal Year Focus	2025
Entity Registrant Name	Harvard Ave Acquisition Corporation
Entity Incorporation, State or Country Code	E9
Entity Central Index Key	0002042460
Entity File Number	001-42887
Entity Tax Identification Number	00-0000000
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q3
Entity Current Reporting Status	No
Entity Shell Company	true
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Address, Address Line One	3rd Floor, 166 Yeongsin-ro
Entity Address, Address Line Two	Yeongdengpo-gu
Entity Address, City or Town	Seoul
Entity Address, Country	KR
Entity Address, Postal Zip Code	07362
City Area Code	+82
Local Phone Number	10-8781-0823
Units, consisting of one Class A ordinary share, $0.0001 par value, and one Right to acquire one-tenth of one Class A ordinary share
Document Information [Line Items]
Title of 12(b) Security	Units, consisting of one Class A ordinary share, $0.0001 par value, and one right to acquire one-tenth of one Class A ordinary share
Trading Symbol	HAVAU
Security Exchange Name	NASDAQ
Class A ordinary shares, $0.0001 par value
Document Information [Line Items]
Title of 12(b) Security	Class A ordinary shares, $0.0001 par value
Trading Symbol	HAVA
Security Exchange Name	NASDAQ
Rights, each whole right to acquire one-tenth of one Class A ordinary share
Document Information [Line Items]
Title of 12(b) Security	Rights, each whole right to acquire one-tenth of one Class A ordinary share
Trading Symbol	HAVAR
Security Exchange Name	NASDAQ
Class A Ordinary Shares
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		15,859,856
Class B Ordinary Shares
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		4,833,333

Harvard Ave Acquisition Corp 10-Q