Reporting to Commander, Naval Air Force, United States Seventh Fleet, she was ordered on to Hollandia, Dutch New Guinea, where she commenced operations with her first seaplane squadron on 26 May 1944.

Orca's squadrons carried out "Black Cat" night bombing and reconnaissance missions during the ensuing five months.

Orca's squadrons also carried out air-sea rescue missions in support of the United States Army's 13th Air Force.

In early November 1944, Orca moved into the Leyte Gulf area in the Philippines, as that campaign was reaching the critical stage.

Heavily loaded, the old Martin PBM Mariners finally heaved themselves into the air, after about a three-nautical-mile (5.6 km) run.

"[5] Orca came under similar attack twice on 26 November 1944, and was credited with an assist on a plane which narrowly missed motor torpedo boat tender USS Oyster Bay (AGP-6).

In the attack, a minesweeper was destroyed and Orca was slightly damaged as a plane crashed close alongside, showering her with wreckage and bomb fragments and wounding six of her gun crew.

Orca continued to service air squadrons and carry out rescue missions until the end of World War II on 15 August 1945.

Orca's next big assignment was furnishing services for Operation Crossroads, the Bikini Atoll atomic bomb tests in 1946.