[6] With her missions accomplished, Gunnel departed the waters off French North Africafor Rosneath, Scotland, on 7 December 1942 to terminate her first patrol.

Subsequently, assigned to the United States Pacific Fleet, Gunnel proceeded to Pearl Harbor, Hawaii, then to her second war patrol (28 May – 3 July 1943) in waters west of Kyūshū in the East China Sea.

After overhaul at Mare Island, California, the submarine accomplished a third war patrol (17 November 1943 – 7 January 1944) in Japanese home waters off Honshū.

The fourth war patrol (5 February – 6 April 1944) took Gunnel from Midway Atoll to Fremantle, Australia, and in the South China, Sulu, and Celebes Seas.

[9] On this same patrol Gunnel evacuated 11 naval aviators at Palawan 1 to 2 December after the fliers had been protected by friendly guerrilla forces for some 2 months.

In the Joint Army-Navy Assessment Committee (JANAC) accounting postwar, she was credited with six ships sunk totaling 24,624 gross register tons.