Cover - shares	9 Months Ended
	Jun. 30, 2024	Aug. 12, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2024
Document Transition Report	false
Entity File Number	1-5103
Entity Registrant Name	BARNWELL INDUSTRIES, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	72-0496921
Entity Address, Address Line One	1100 Alakea Street
Entity Address, Address Line Two	Suite 500
Entity Address, City or Town	Honolulu
Entity Address, State or Province	HI
Entity Address, Postal Zip Code	96813
City Area Code	808
Local Phone Number	531-8400
Title of 12(b) Security	Common Stock, $0.50 par value
Trading Symbol	BRN
Security Exchange Name	NYSEAMER
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		10,028,090
Entity Central Index Key	0000010048
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Amendment Flag	false