    <SEC-DOCUMENT>0001193125-23-270150-index.html : 20231103
    <SEC-HEADER>0001193125-23-270150.hdr.sgml : 20231103
    <ACCEPTANCE-DATETIME>20231103120836
    ACCESSION NUMBER:		0001193125-23-270150
    CONFORMED SUBMISSION TYPE:	N-CSRS
    PUBLIC DOCUMENT COUNT:		3
    CONFORMED PERIOD OF REPORT:	20230831
    FILED AS OF DATE:		20231103
    DATE AS OF CHANGE:		20231103
    EFFECTIVENESS DATE:		20231103

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			NUVEEN CALIFORNIA SELECT TAX FREE INCOME PORTFOLIO
    		CENTRAL INDEX KEY:			0000885732
    		IRS NUMBER:				363828111
    		STATE OF INCORPORATION:			MA

    	FILING VALUES:
    		FORM TYPE:		N-CSRS
    		SEC ACT:		1940 Act
    		SEC FILE NUMBER:	811-06623
    		FILM NUMBER:		231375166

    	BUSINESS ADDRESS:
    		STREET 1:		333 W WACKER DR
    		CITY:			CHICAGO
    		STATE:			IL
    		ZIP:			60606
    		BUSINESS PHONE:		3129178200

    	MAIL ADDRESS:
    		STREET 1:		333 W WACKER DRIVE
    		CITY:			CHICAGO
    		STATE:			IL
    		ZIP:			60606

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	NUVEEN INSURED CALIFORNIA SELECT TAX FREE INCOME PORTFOLIO
    		DATE OF NAME CHANGE:	19920929

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	NUVEEN CALIFORNIA SELECT TAX FREE INCOME PORTFOLIO
    		DATE OF NAME CHANGE:	19600201
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>N-CSRS
    <SEQUENCE>1
    <FILENAME>d446452dncsrs.htm
    <DESCRIPTION>NUVEEN CALIFORNIA SELECT TAX-FREE INCOME PORTFOLIO
    <TEXT>
    Document 1 - file: d446452dncsrs.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.CERT
    <SEQUENCE>2
    <FILENAME>d446452dex99cert.htm
    <DESCRIPTION>CERTIFICATION PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT
    <TEXT>
    Document 2 - file: d446452dex99cert.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.906CERT
    <SEQUENCE>3
    <FILENAME>d446452dex99906cert.htm
    <DESCRIPTION>CERTIFICATION PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT
    <TEXT>
    Document 3 - file: d446452dex99906cert.htm

    </DOCUMENT>
    </SEC-DOCUMENT>