Shakedown complete, "Catoctin" cleared Norfolk 5 March 1944 for Algiers, where she reported on 19 March as flagship for Commander, 8th Fleet. She remained at Algiers and later Oran until 8 July, when she sailed to Naples, Italy. On 24 July, at Naples, King George VI of the United Kingdom visited on board the ship. For several months, "Catoctin" had been headquarters for the planning of the Invasion of Southern France, and on 13 August, she sailed from Naples for the assault, carrying Secretary of the Navy James Forrestal, and the commanders of the 7th Army, VI Corps, 12th Air Force, and French Naval Forces.