Following commissioning, S-34 was ordered to New London, Connecticut, for engineering alterations by the prime contractor, the Electric Boat Company.

She departed from San Francisco, California, in mid-April, arrived at the Submarine Base, Cavite, P.I., on 12 July; and, after voyage repairs and an overhaul, commenced operations as a unit of the Asiatic Fleet.

From then until 1932, she rotated between exercises, patrols, and overhauls in the Philippines during the winter and deployments to the China coast in the summer for operations out of Tsingtao.

However, with the new year, 1942, she and other World War I design submarines were ordered prepared for service in the northern Pacific in defense of the Aleutian Islands.

She underwent overhaul at Mare Island, and, in March, she moved north to the newly established submarine base at Dutch Harbor, Unalaska.

One day out, a heavy wave threw the quartermaster of the watch against the side of the bridge, and S-34 was forced to return to base to put the badly injured man ashore.

On 20 April, she left the Bering Sea and entered the less violent, but fog shrouded, waters of the Kuril Islands.

Ice, two to five feet above the water, still covered the area and the boat retired through the strait to patrol on the Pacific side of the island.

Thence, she continued on to Kiska; remained offshore on 2 May as a storm battered the island; and, on 3 May, she replenished and moved north to intercept any enemy submarines which might be heading for the Gulf of Alaska.

Refit as intelligence estimates predicting a Japanese thrust at Midway Island and the Aleutians were received, S-34 cleared Dutch Harbor on 28 May and stood west to patrol north of Attu.

On 29 May, the Japanese Aleutian force sortied from Ominato and headed east, its approach to its target covered by fog and rain.

From the start of her patrol until 11 June, S-34 remained in her assigned area, listening to reports, but sighting no enemy ships.

On 20 September, while off Buldir, her after radio mast was partially carried away by heavy seas and threatened to foul the propellers and stern planes.

Despite the heavy seas, Chief Machinist's Mate B.F. Allen went over the side; cut the wreckage adrift and rigged two forward wing antennas.

A week later, she sighted and closed a Kiska-bound enemy submarine; but, as the torpedoes were readied, depth control was lost; and she failed to score.

On 18 January, she arrived at San Diego where she remained until late April, undergoing overhaul; receiving radar, air conditioning, and improved communication and navigation equipment, and providing services to the West Coast Sound School.

On the evening of 31 May 1943, she mistakenly torpedoed and sank the Soviet 2,600-gross register ton survey ship Chukcha[1] off Torishimo Retto.

On 28 June, she approached the fog-bound Kurils; and, on 1 July, she moved toward the Kamchatka Peninsula to locate and destroy enemy fishing vessels operating near and north of Cape Lopatka.