Upon "I-36"′s arrival, her commanding officer received a briefing on the situation in the Aleutians from the commander of Submarine Squadron 1. The Americans had annihilated the Japanese garrison on Attu during the Battle of Attu of 11–30 May 1943, isolating the last remaining Japanese garrison on Kiska. Even before the fall of Attu, Japanese Imperial General Headquarters had decided on 21 May 1943 to evacuate the Kiska garrison by submarine beginning on 26 May 1943. "I-36" was assigned to the effort to keep the Kiska garrison supplied while continuing the ongoing evacuation.