Aleutian Islands campaign
With her repairs complete, S-18 departed San Diego, in May 1942, to return to the Aleutians. While enroute, on 29 May 1942, she received orders to patrol the southern approaches to Umnak Pass, in anticipation of a Japanese attack, and on 2 June 1942, she took up her patrol station. On 3 June 1942, planes from the Japanese Navy aircraft carriers Ryūjō and Jun'yō attacked Dutch Harbor. commencing the Battle of Dutch Harbor of 3–4 June 1942 and beginning the Aleutian islands campaign. Soon afterward, Japanese troops landed troops on Kiska and Attu.
Hampered by fog, rain, and poor radio reception; and lacking radar, a fathometer, and deciphering equipment; S-18 remained on patrol through 10 June 1942. Orders for submerged daylight operations in combat areas, compelled S-18, and the other the World War I design submarines of the North Pacific Force, to increase their submerged time to 19 hours a day, with surfaced recharging time cut to the brief five hours of the northern summer night. On 11 June 1942, she returned to Dutch Harbor.
On 13 June 1942, S-18 was underway again to patrol west and north of Attu, then north of Kiska. The weather, as on earlier patrols, was consistently bad. Habitability in the S-boats was poor. Material defects and design limitations in speed and maneuverability continued to plague her. On 29 June 1942, she sighted a Japanese submarine, but was unable to close. The same day, she returned to Dutch Harbor, and as at the conclusion of previous patrols, her commanding officer requested up-to-date sound and radar equipment.
From 15 July to 2 August 1942, S-18 conducted another patrol in the Kiska area, and on completion of that patrol, she was ordered back to San Diego.
In October 1942, S-18 returned to the Aleutians, and on 22 October 1942, she cleared Dutch Harbor, for her next patrol, again in the Kiska area. On 3 November 1942, however, she was recalled and ordered to prepare for a longer, more distant patrol. On 12 November 1942, she put to sea, but on 15 November 1942, a crack in the starboard main engine housing forced her back to Dutch Harbor.
She arrived on 20 November 1942, and her repairs were completed by the end of the month. On 30 November 1942, S-18 resumed her patrol, moved west, and operated off Kiska, Kiskinato, Agattu, and Attu. On 22 December 1942, after 16 days in her patrol area, she lost her starboard stern plane, and depth control became erratic. On 28 December 1942, she returned to Dutch Harbor.
Repairs and refit took S-18 into 1943, and on 7 January 1943, she got underway again. During that 28-day patrol, she reconnoitered Attu, and the Semichi Islands. On 4 February 1943, she was ordered back to San Diego, for overhaul.
United States
