Following underway trials, training and shakedown in the Portsmouth, New Hampshire and New London, Connecticut areas, USS SEA POACHER (SS-406) transited the Panama Canal and arrived at Pearl Harbor on 25 October 1944. Although her first two war patrols were unproductive, during the third, conducted in the Kuril Islands area, SEA POACHER torpedoed and sank a Japanese trawler and, four days later, sent two fishing boats to the bottom in a surface attack. During the latter action, three crewmen were injured when the 20mm gun exploded. Due to the seriousness of their injuries, the patrol was terminated ahead of schedule, and the submarine returned to Midway.

After conducting her fourth war patrol off the eastern coast of Honshu and Hokkaido, SEA POACHER was undergoing refitting at Pearl Harbor when the war ended on 15 August 1945.

From 1946 to 1949, SEA POACHER was based at Balboa, Canal Zone, as a unit of SubRon6 engaging in fleet exercises and antisubmarine training, and, on 1 June 1949, was transferred to Key West, Florida as a unit of SubRon4. In 1951, the submarine became the first GUPPY IA conversion performed at the Charleston Naval Shipyard.

For the remainder of her 25-year career, SEA POACHER operated for the most part in the Key West, and Caribbean areas, providing services to various units of the Atlantic Fleet with time out for tours of duty with the 6th Fleet in the Mediterranean and various exercises with NATO forces. On 10 July 1952, while operating in the Key West area, the submarine had the unique experience of rescuing a blimp which had suffered an engine casualty and was floating helplessly in the water. The submarine promptly came to the aid of the stricken airship and proceeded to tow it the 40 miles back to its base at the U.S. Naval Air Station, Boca Chica, Florida.

In July 1969, SEA POACHER concluded her service with a three and one-half month deployment to the eastern and northern Atlantic areas to participate in antisubmarine training exercises with units of the Spanish and Portuguese navies. Upon returning to Key West, the submarine operated locally and in the Caribbean until 20 October when she set sail for Philadelphia and inactivation. SEA POACHER was reclassified as auxiliary submarine (AGSS) on 1 November, decommissioned on 15 November 1969, and was assigned to the Atlantic Reserve Fleet at Philadelphia. On 30 June 1971, she reassumed the designation of a fleet submarine (SS). On 15 August 1973, her name was struck from the Navy List, and the submarine was sold to Peru in July 1974.

Renamed La Pedrera it was kept in their service until 1993 when it was decommissioned again and sold for scrap. While being towed to the breakdown yard a storm came up and the tow line parted. The Sea Poacher now rests on the beach at the end of the Calio airport runway.

SEA POACHER received four battle stars for her service during World War II.