The submarine Grunion arrived at Pearl Harbor on June 20, 1942. The vessel completed pre-patrol training before departing on its first war patrol June 30. Grunion's commanding officer, Lt. Cmdr. Abele, was ordered to proceed to the Aleutian Islands and patrol westward from Attu on routes between the Aleutians and the Japanese Empire.
On July 10, Grunion was reassigned to the area north of Kiska. Over the next 20 days, the submarine reported firing on an enemy destroyer, sinking three destroyer-type vessels, and attacking unidentified enemy ships near Kiska.
Grunion's last transmission was received on July 30, 1942. The submarine reported heavy antisubmarine activity at the entrance to Kiska, and that it had 10 torpedoes remaining forward.
On the same day, Grunion was directed to return to Dutch Harbor Naval Operating Base. There was no contact or sighting of the submarine after July 30, and on August 16, Grunion was reported lost.