Bojeador, she shifted south to the Vigan area on 20 December, and on 23 December, torpedoed and sank , the last Japanese ship sunk by American torpedoes in December 1941. 1942 From the Vigan area, the submarine moved into the approaches to Lingayen Gulf, and in January 1942, she again turned north to patrol the entrance to Lamon Bay. She rounded Cape Bojeador on 9 January and Cape Engaño on 10 January, and, on 11 January—as the Japanese invaded the Netherlands East Indies at Tarakan, Borneo, and Minahasa, Celebes—she headed south for the Molucca Passage. By 20 January, she was patrolling east of the Celebes to intercept enemy traffic into Kema. On 27 January, she was ordered to patrol off Kendari, which had been attacked on 24 January and then to proceed to the Royal Netherlands Naval Base at Soerabaja, then still under Allied control. Seal arrived at Soerabaja on 5 February. Daily air raids necessitated diving during the day and precluded repairs to her engines, which smoked excessively, and to the broken prism control mechanism in her high periscope. On 11 February, she departed for Tjilatjap on the south coast of Java, and on 14 February, she went alongside . That same day, the Japanese moved into southern Sumatra, and on 19 February, they invaded Bali. Allied forces counterattacked, and as air and surface forces hit the Japanese fleet, Seal departed Tjilatjap and transited Lombok Strait to patrol north of Java. On 24 February, she attacked two convoys, only damaging one freighter. The next day, she unsuccessfully attacked an enemy warship formation. On 1 March, as the Japanese moved against Soerabaja, she was similarly disappointed. On 14 March, she headed east to patrol the southern approaches to Makassar City, and for the next week, with her forward air conditioning unit broken down and her refrigerating plant inoperable, she patrolled between that city and De Bril Bank. On 21 March, she headed for Fremantle, Western Australia—the Netherlands East Indies had fallen. Arriving on 9 April, Seal departed again on 12 May and worked her way through the Malay Archipelago, the Celebes Sea, and the Sulu Sea to her patrol area off the Indochina coast. During the early morning hours of 28 May, she entered the South China Sea, and that night, she fired on and sank 1,946-ton Tatsufuku Maru. On 7 June, while off Cam Ranh Bay, she attacked an