Document and Entity Information	Jun. 28, 2024
Entity Listings [Line Items]
Document Type	8-K
Amendment Flag	false
Document Period End Date	Jun. 28, 2024
Entity File Number	001-41021
Entity Registrant Name	MOUNTAIN & CO. I ACQUISITION CORP.
Entity Central Index Key	0001856995
Entity Incorporation, State or Country Code	E9
Entity Tax Identification Number	00-0000000
Entity Address, Address Line One	4001 Kennett Pike
Entity Address, Address Line Two	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 Emerging Growth Company	true
Entity Ex Transition Period	false
Written Communications	false
Soliciting Material	false
Pre-commencement Tender Offer	false
Pre-commencement Issuer Tender Offer	false
Class A ordinary shares, par value $0.0001 per share [Member]
Entity Listings [Line Items]
Title of 12(b) Security	Class A ordinary shares, par value $0.0001 per share
Trading Symbol	MCAA
Security Exchange Name	NASDAQ
Redeemable warrants, each whole warrant exercisable for one Class A ordinary share at an exercise price of $11.50 [Member]
Entity Listings [Line Items]
Title of 12(b) Security	Redeemable warrants, each whole 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 [Member]
Entity Listings [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