Document and Entity Information - USD ($)	9 Months Ended
	Dec. 31, 2021	Apr. 15, 2022	Jun. 30, 2021
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2021
Entity File Number	001-41021
Entity Registrant Name	Mountain & Co. I Acquisition Corp.
Entity Incorporation, State or Country Code	E9
Entity Tax Identification Number	00-0000000
Entity Address, Address Line One	4001 Kennett Pike, Suite 302
Entity Address, City or Town	Wilmington
Entity Address State Or Province	DE
Entity Address, Postal Zip Code	19807
City Area Code	302
Local Phone Number	273-0765
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
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
ICFR Auditor Attestation Flag	false
Entity Ex Transition Period	false
Entity Shell Company	true
Entity Public Float			$ 0
Entity Central Index Key	0001856995
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false
Auditor Name	Marcum LLP
Auditor Firm ID	688
Auditor Location	New York, New York
Class A Common Stock
Document Information [Line Items]
Title of 12(b) Security	Class A ordinary shares, par value $0.0001 per share
Trading Symbol	MCAA
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		23,000,000
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		5,750,000
Redeemable warrants, each whole warrant exercisable for one Class A ordinary share at an exercise price of $11.50
Document Information [Line Items]
Title of 12(b) Security	Redeemable warrants, each warrant exercisable for one Class A ordinary share at an exercise price of $11.50
Trading Symbol	MCAAW
Security Exchange Name	NASDAQ
Units, each consisting of one Class A ordinary share and one-half of one redeemable warrant
Document Information [Line Items]
Title of 12(b) Security	Units, each consisting of one Class A ordinary share and one-half of one redeemable warrant
Trading Symbol	MCAAU
Security Exchange Name	NASDAQ