Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Aug. 12, 2021
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Entity Registrant Name	SUPERNOVA PARTNERS ACQUISITION COMPANY II, LTD.
Entity Central Index Key	0001838359
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	true
Entity Current Reporting Status	No
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	E9
Entity File Number	001-40140
Entity Tax Identification Number	98-1574543
Entity Address, Address Line One	4301 50th Street NW
Entity Address, Address Line Two	Suite 300 PMB 1044
Entity Address, City or Town	Washington
Entity Address, State or Province	DC
Entity Address Postal Zip Code	20016
City Area Code	202
Local Phone Number	918-7050
Document Quarterly Report	true
Document Transition Report	false
Units
Document Information [Line Items]
Title of 12(b) Security	Units, each consisting of one Class A ordinary share, $0.0001 par value, and one-fourth of one redeemable warrant
Trading Symbol	SNII.U
Security Exchange Name	NYSE
Class A Ordinary Shares
Document Information [Line Items]
Title of 12(b) Security	Class A ordinary share, par value $0.0001 per share
Trading Symbol	SNII
Security Exchange Name	NYSE
Entity Common Stock, Shares Outstanding		34,500,000
Warrants
Document Information [Line Items]
Title of 12(b) Security	Warrants, each whole warrant exercisable for one Class A ordinary share at an exercise price of $11.50 per share
Trading Symbol	SNII WS
Security Exchange Name	NYSE
Class B Ordinary Shares
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		8,625,000