"Humboldt" moved to the Philadelphia Navy Yard in Philadelphia, Pennsylvania, on 16 July 1945, for conversion to a press information ship. Reclassified as a miscellaneous auxiliary and redesignated AG-121 on 30 July 1945, "Humboldt" was to serve as a broadcast and teletype center for correspondents during the planned invasion of Japan in 1945–1946. However, hostilities with Japan ended on 15 August 1945, making the invasion unnecessary before her conversion was completed.