Cover - USD ($)	12 Months Ended
	Dec. 31, 2025	Mar. 05, 2026	Jun. 30, 2025
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Financial Statement Error Correction [Flag]	false
Entity Interactive Data Current	Yes
ICFR Auditor Attestation Flag	false
Amendment Flag	false
Document Period End Date	Dec. 31, 2025
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	FY
Entity Information [Line Items]
Entity Registrant Name	Melar Acquisition Corp. I/Cayman
Entity Central Index Key	0002016221
Entity File Number	001-42134
Entity Tax Identification Number	87-1634103
Entity Incorporation, State or Country Code	E9
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
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 Public Float			$ 168,160,000
Entity Contact Personnel [Line Items]
Entity Address, Address Line One	143 West 72nd Street
Entity Address, Address Line Two	4th Floor
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10023
Entity Phone Fax Numbers [Line Items]
City Area Code	(702)
Local Phone Number	781-1120
Units, each consisting of one Class A Ordinary Share and one-half of one redeemable Warrant
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	MACIU
Security Exchange Name	NASDAQ
Class A Ordinary Shares, par value $0.0001 per share
Entity Listings [Line Items]
Title of 12(b) Security	Class A Ordinary Shares, par value $0.0001 per share
Trading Symbol	MACI
Security Exchange Name	NASDAQ
Warrants, each whole Warrant exercisable for one Class A Ordinary Share at an exercise price of $11.50 per share
Entity Listings [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	MACIW
Security Exchange Name	NASDAQ
Class A Ordinary Shares
Entity Listings [Line Items]
Entity Common Stock, Shares Outstanding		16,000,000
Class B Ordinary Shares
Entity Listings [Line Items]
Entity Common Stock, Shares Outstanding		5,621,622