Cover - shares	3 Months Ended
	Mar. 31, 2022	May 06, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2022
Document Transition Report	false
Entity File Number	001-35633
Entity Registrant Name	Sound Financial Bancorp, Inc.
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	45-5188530
Entity Address, Address Line One	2400 3rd Avenue,
Entity Address, Address Line Two	Suite 150,
Entity Address, City or Town	Seattle,
Entity Address, State or Province	WA
Entity Address, Postal Zip Code	98121
City Area Code	206
Local Phone Number	448-0884
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	SFBC
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		2,616,431
Entity Central Index Key	0001541119
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1