Document and Entity Information - shares		6 Months Ended
		Jun. 30, 2026	Aug. 05, 2026
Document and Entity Information
Document Type		10-Q
Document Quarterly Report		true
Document Period End Date		Jun. 30, 2026
Document Transition Report		false
Securities Act File Number		001-39231
Entity Registrant Name		Passage BIO, Inc.
Entity Incorporation, State or Country Code		DE
Entity Tax Identification Number		82-2729751
Entity Address, Address Line One	[1]	Address Not Applicable
Entity Address, City or Town	[1]	Address Not Applicable
Entity Address, Postal Zip Code		ZIP Code Not Applicable
City Area Code		267
Local Phone Number		866-0311
Title of 12(b) Security		Common Stock
Trading Symbol		PASG
Security Exchange Name		NASDAQ
Entity Current Reporting Status		Yes
Entity Interactive Data Current		Yes
Entity Filer Category		Non-accelerated Filer
Entity Small Business		true
Entity Emerging Growth Company		false
Entity Shell Company		false
Entity Common Stock, Shares Outstanding			3,217,810
Entity Central Index Key		0001787297
Current Fiscal Year End Date		--12-31
Document Fiscal Year Focus		2026
Document Fiscal Period Focus		Q2
Amendment Flag		false

[1] We are a remote-only company. Accordingly, we do not maintain a headquarters. For purposes of compliance with applicable requirements of the Securities Act and Securities Exchange Act of 1934, as amended, any stockholder communication required to be sent to our principal executive offices may be directed to P.O. Box 7, Hopewell, New Jersey 08525.