6-inch guns were removed and another eighteen single mounts installed. In October 1944, Kongō departed from Lingga in preparation for "Operation Sho-1", Japan's counterattack during the Battle of Leyte Gulf, the largest naval engagement in history. On 24 October, Kongō was undamaged by several near misses from American carrier aircraft in the Battle of the Sibuyan Sea. On 25 October, during the Battle off Samar, Kongō—as part of Admiral Kurita's Centre Force—engaged the US 7th Fleet's "Taffy 3", a battlegroup of escort carriers and destroyers. She succeeded in scoring numerous hits on the escort carrier as well as the destroyers and . At 09:12, she sank the destroyer escort . After a fierce defensive action by the American ships, which sank three Japanese heavy cruisers, Admiral Kurita elected to withdraw, ending the battle. While retreating, Kongō suffered damage from five near misses from attacking aircraft. The fleet arrived at Brunei on 28 October. On 16 November, following a US air raid on Brunei, Kongō along with , and the rest of the First Fleet, departed from Brunei bound for Kure in preparation for a major reorganization of the fleet and battle repairs. On 20 November, they entered the Formosa Strait. Shortly after midnight on 21 November, the submarine made radar contact with the fleet at . Maneuvering into position at 02:45, Sealion fired six bow torpedoes at Kongō followed by three stern torpedoes at Nagato fifteen minutes later. One minute after the first salvo was launched, two of the torpedoes were seen to hit Kongō on the port side, while a third sank the destroyer with all hands. The torpedoes flooded two of Kongōs boiler rooms, but she was still able to make . By 05:00, she had slowed to and was given permission to break off from the fleet and head to the port of Keelung in Formosa along with the destroyers and as escort. Within fifteen minutes of detaching from the main force, Kongō was listing 45 degrees and flooding uncontrollably. At 5:18 the ship lost all power and the order was given to abandon ship. At 5:24, while the evacuation was under way, the forward 14-inch magazine exploded, and the broken ship sank quickly, with the loss of over 1,200 of her crew, including the commander of the Third Battleship Division and her captain. Kongō is believed to have sunk in of water approximately northwest of Keelung.