Sand Lance encountered her first victim, the Japanese cargo ship Kaika Maru, taking shelter from a blizzard in the lee of Paramushiro's southeast point and torpedoed and sank her.

On 3 March 1944, Sand Lance mistakenly sank the Soviet merchant ship Byelorussia in the Sea of Okhotsk.

[7][8] On the night of 12–13 March, Sand Lance was running on the surface toward Honshū when a marauding airplane forced her to submerge.

Eight days later, she damaged Mitakesan Maru, a 4441-ton passenger cargo ship, while evading the bombs from an attacking enemy plane.

Sand Lance sent the 4291-ton freighter Koho Maru to the bottom on 14 May off Apra Harbor, Guam, and found two more targets off Saipan on 17 May.

Four days later, she received a good shaking from fast patrol craft while trying to press an attack on a large transport in the Sulu Islands.

Soon, Sand Lance had two additional problems, enemy escorts bearing down on her and a torpedo running hot in one of her stern tubes.

On her fourth war patrol from 10 April to 6 June 1945, Sand Lance encountered only one target, an unidentified coastal freighter which she torpedoed on 14 May.

Hostilities ceased on 15 August, and, on the next day Sand Lance made for San Francisco, California, via Midway and Pearl Harbor.

Sand Lance remained inactive until designated for loan to the Brazilian Navy under the terms of the Military Assistance Program.

She departed Pearl Harbor on 24 June and made San Francisco on 1 July to embark officers and men of the Brazilian Navy for training.

Sand Lance (SS-381) earned five battle stars and a Presidential Unit Citation for World War II service.