On 13 January, BARBEL was directed to join USS BLUEGILL (SS-242) and USS BREAM (SS-243) in covering the western approaches to Balabac Strait. On 27 January she was ordered to form a wolfpack with USS PERCH II (SS-313) and USS GABILAN (SS-252) and cover the western approaches to Balabac and southern entrance to Palawan Passage.
On 3 February 1945 BARBEL sent a message to USS TUNA II (SS-203), USS BLACKFIN (SS-322) and GABILAN reporting numerous aircraft contacts daily. BARBEL had been attacked by aircraft three times with depth charges, and would transmit a message "tomorrow night" giving information. This was the last contact with BARBEL. TUNA reported on 6 February 1945 that she had been unable to contact BARBEL for 48 hours, and that she had ordered her to rendezvous at 7!-30'N;115!-30'E on 7 February. The rendezvous was not accomplished and TUNA reported her search unsuccessful on 7 February 1945.
Japanese records indicate that on 4 February 1945 a plane attacked a submarine in position 7!-49'N;116!-47.5'E scoring one hit near the bridge with one of two bombs dropped. It appears almost certain that this attack sank BARBEL.
BARBEL sank 10 ships for 55,200 tons and damaged two ships for 14,000 tons during her three completed patrols. Her first was made in the Nansei Shoto chain. She sank three medium freighters, a large freighter of 19,600 tons, and a large tanker. In the same area on her second patrol, BARBEL sank a freighter and two escort vessels. She also damaged another freighter and a tanker. During her third patrol, conducted in the South China Sea, BARBEL sank two medium freighters.
BARBEL received three battle stars for her World War II
service.