Document And Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Aug. 05, 2021
Document Information Line Items
Entity Registrant Name	Motion Acquisition Corp.
Trading Symbol	MOTN
Document Type	10-Q
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Entity Central Index Key	0001822359
Entity Current Reporting Status	No
Entity Filer Category	Non-accelerated Filer
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Shell Company	true
Entity Ex Transition Period	false
Document Quarterly Report	true
Document Transition Report	false
Entity Incorporation, State or Country Code	DE
Entity File Number	001-39618
Entity Tax Identification Number	85-2515483
Entity Address, Address Line One	c/o Graubard Miller
Entity Address, Address Line Two	The Chrysler Business
Entity Address, Address Line Three	405 Lexington Avenue
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10174
City Area Code	(212)
Local Phone Number	818-8800
Title of 12(b) Security	Class A common stock, par value $0.0001 per share
Security Exchange Name	NASDAQ
Entity Interactive Data Current	Yes
Class A Common Stock
Document Information Line Items
Entity Common Stock, Shares Outstanding		11,500,000
Class B Common Stock
Document Information Line Items
Entity Common Stock, Shares Outstanding		2,875,000