Document and Entity Information - shares	9 Months Ended
	Jun. 30, 2020	Aug. 01, 2020
Entity Registrant Name	OneWater Marine Inc.
Entity Central Index Key	0001772921
Current Fiscal Year End Date	--09-30
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Entity Address, State or Province	GA
Common Class A [Member]
Entity Common Stock, Shares Outstanding		6,087,906
Common Class B [Member]
Entity Common Stock, Shares Outstanding		8,462,392