After patrolling for a month without spotting anything but aircraft, she surfaced on the afternoon of September 25, 1944 and her lookouts spied a convoy of three Japanese merchant ships escorted by a destroyer.

She had a similar experience on October 8, 1944 when she launched torpedoes at a heavily escorted tanker north of Palawan Passage in the Philippine Islands.

Again her crew heard two distinct explosions but were too busy dodging depth charges to observe the results of the attack.

On October 9, 1944, however, she recorded her first verifiable success when she joined the submarine USS Hawkbill (SS-366) in sinking the 1,943-gross register ton Japanese cargo ship Tokuwa Maru.

She cruised the waters of the South China Sea off the southern coast of Japanese-occupied French Indochina searching for Japanese fleet units.

Lack of time prevented her from achieving a favorable setup before they entered Cam Ranh Bay on the coast of French Indochina.

She destroyed floating naval mines and, on her way back to Fremantle, sank two "sea trucks" — the American term for a type of small Japanese cargo ship — with her deck gun just north of Lombok Strait.

She returned to the South China Sea off the coast of French Indochina, where she encountered a Japanese convoy off Cap Padaran on the morning of February 22, 1945.

She sighted no other Japanese shipping, and her patrol ended with her arrival at Subic Bay on Luzon in the Philippine Islands, where she underwent a refit.

They all missed, but the submarine USS Baya (SS-318) took up the chase and sank the vessel, the Ambon Island-bound Japanese torpedo boat Kari.

She then served in the United States Pacific Fleet until 1949, conducting submarine crew training missions and participating in various multiship exercises.

She received additional batteries, a submarine snorkel, and a streamlined sail as well as a number of other modifications to various items of equipment.

Becuna was placed on permanent display adjacent to the cruiser USS Olympia (C-6) at Penn's Landing in Philadelphia, Pennsylvania, on June 21, 1976.