After shakedown, Knox departed Naval Base Norfolk on 6 April 1944 for the Pacific, arriving Pearl Harbor 23 April with U.S. Marines and Seabees embarked. Assigned to the 5th Amphibious Force, the transport sailed 29 May as part of Task Force 52 bound for the Marianas. Steaming via Eniwetok, Marshall Islands, Knox arrived off Saipan 15 June and made a diversionary landing at Garapan before debarking her troops that afternoon at the actual landing area. She remained off Saipan until 24 June, then sailed for Eniwetok, arriving the 28th with Saipan casualties on board.