Cover - shares	9 Months Ended
Cover - 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
Document Fiscal Period Focus	Q3
Entity Registrant Name	AA Mission Acquisition Corp. II
Entity Central Index Key	0002075336
Entity File Number	001-42886
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
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 Tax Identification Number	00-0000000
Entity Incorporation, State or Country Code	E9
Entity Address, Address Line One	21 Waterway Avenue
Entity Address, Address Line Two	STE 300 #9733
Entity Address, City or Town	The Woodlands
Entity Address, State or Province	TX
City Area Code	(832)
Local Phone Number	336-8887
Entity Address, Postal Zip Code	77380
Units, Each Consisting of One Class A Ordinary Share and One-Half of One Warrant
Document Information [Line Items]
Title of 12(b) Security	Units, each consisting of one Class A ordinary share and one-half of one warrant
Trading Symbol	YCY.U
Security Exchange Name	NYSE
Class A Ordinary Shares, Par Value $0.0001 Per Share
Document Information [Line Items]
Title of 12(b) Security	Class A ordinary shares, par value $0.0001 per share
Trading Symbol	YCY
Security Exchange Name	NYSE
Warrants, Each Whole Warrant Entitles the Holder Thereof to Purchase One Class A Ordinary Share at A Price of $11.50 Per Share
Document Information [Line Items]
Title of 12(b) Security	Warrants, each whole warrant entitles the holder thereof to purchase one Class A ordinary share at a price of $11.50 per share
Trading Symbol	YCY.WS
Security Exchange Name	NYSE
Class A Ordinary Shares
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		11,860,250
Class B Ordinary Shares
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		2,875,000

AA Mission Acquisition Corp. II 10-Q