"George Clymer" continued troop-carrying and supply runs in the Southwest Pacific until 4 June 1944 when she departed Guadalcanal for the invasion of the Marianas. Steaming via Kwajalein, she operated off Saipan from 17 to 30 June while serving as flagship of Rear Admiral Lawrence Fairfax Reifsnider's Southern Attack Group. She reached Eniwetok 4 July; departed 17 July for the assault against Guam - and arrived off Agat 21 July. After debarking assault troops, she served as receiving ship, boat pool tender, and medical station for the Southern Transport Group. She remained at Guam until 20 August; steamed via Saipan to Hawaii; and arrived Pearl Harbor 31 August.