Document And Entity Information - Jun. 30, 2015 - shares	Total
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2015
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	Q1
Entity Registrant Name	BOSTON CAPITAL TAX CREDIT FUND III L P
Entity Central Index Key	0000879555
Current Fiscal Year End Date	--03-31
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding	0