Assigned to the British 8th Submarine Flotilla, "Zwaardvisch" operated out of Fremantle, Western Australia, after September 1944, at which time she was placed under the operational command of the US fleet. In October, she also sank the Japanese guardboat "Koei Maru", the Japanese oceanographic research vessel "Kaiyō No.2" and the . She also damaged the . On 6 October 1944, she sank the German submarine with a spread of six torpedoes, hitting the U-168 twice, one torpedo detonating in the U-168's forward torpedo room. The submarine had been on a patrol around Java when she received directions via radio to establish an ambush off Surabaya, where she subsequently torpedoed and sank "U-168", which had been on its way to Japan to transfer important military technologies.