    <SEC-DOCUMENT>0000887343-25-000154-index.html : 20250403
    <SEC-HEADER>0000887343-25-000154.hdr.sgml : 20250403
    <ACCEPTANCE-DATETIME>20250403163540
    ACCESSION NUMBER:		0000887343-25-000154
    CONFORMED SUBMISSION TYPE:	DEFA14A
    PUBLIC DOCUMENT COUNT:		4
    FILED AS OF DATE:		20250403
    DATE AS OF CHANGE:		20250403

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			COLUMBIA BANKING SYSTEM, INC.
    		CENTRAL INDEX KEY:			0000887343
    		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
    		ORGANIZATION NAME:           	02 Finance
    		EIN:				911422237
    		STATE OF INCORPORATION:			WA
    		FISCAL YEAR END:			1231

    	FILING VALUES:
    		FORM TYPE:		DEFA14A
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	000-20288
    		FILM NUMBER:		25810135

    	BUSINESS ADDRESS:
    		STREET 1:		1301 A STREET
    		CITY:			TACOMA
    		STATE:			WA
    		ZIP:			98402
    		BUSINESS PHONE:		2533051900

    	MAIL ADDRESS:
    		STREET 1:		1301 A STREET
    		CITY:			TACOMA
    		STATE:			WA
    		ZIP:			98402

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	COLUMBIA BANKING SYSTEM INC
    		DATE OF NAME CHANGE:	19930328
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>DEFA14A
    <SEQUENCE>1
    <FILENAME>defa14a2025.htm
    <DESCRIPTION>DEFA14A
    <TEXT>
    Document 1 - file: defa14a2025.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>2
    <FILENAME>columbiabankingsysteminc_v.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 2 - file: columbiabankingsysteminc_v.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>3
    <FILENAME>columbiabankingsysteminc_va.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 3 - file: columbiabankingsysteminc_va.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>4
    <FILENAME>image_2.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 4 - file: image_2.jpg

    </DOCUMENT>
    </SEC-DOCUMENT>