1943 The submarine arrived Brisbane 31 January 1943 and remained there until departing on her fifth war patrol 21 February. Greenling steamed to the Solomons–Bismarck area, and landed a party of intelligence agents on the coast of New Britain 2 March. In a patrol characterized by bad weather, she scored no hits on enemy shipping and returned to Brisbane 26 April 1943. Greenling cleared Brisbane 17 May to conduct her sixth war patrol, in the Solomons–New Guinea area, long the scene of bitter sea and land fighting. During this patrol she damaged oiler Akebono Maru on 9 June, and is also alleged to damaged ships on 10 June, and 27 June, but was unable to record a sinking because of heavy escort activity. She returned to Brisbane 8 July 1943. Seventh war patrol, July – September 1943 The submarine sailed 29 July on her seventh war patrol, which consisted largely of special missions. She landed a party of Marine Raiders in the Treasury Islands 22 – 23 August to select a site for a radar station and prepare for the landings there, scheduled for October. Greenling reconnoitered Tarawa 10 September and sailed to San Francisco via Pearl Harbor for overhaul. Eighth and ninth war patrols, December 1943 – May 1944 Returning to Pearl Harbor 5 December, Greenling sailed for her eighth war patrol 20 December 1943, in the Caroline Islands. She ended the old year with a late night attack, sinking freighter Shōhō Maru, reconnoitred Wake Island, and returned to Midway 28 January 1944. Her ninth war patrol, 20 March – 12 May 1944, was a special mission entailing photographic reconnaissance of Guam, Tinian, and Saipan in the Marianas Islands, work which did much to aid the coming amphibious campaign for the Marianas. Tenth and eleventh war patrols, July – November 1944 Greenling sailed from Pearl Harbor on her 10th patrol 9 July 1944. Operating off Formosa, she formed a coordinated attack unit ("wolfpack") with and . Closely watched by enemy aircraft, Greenling recorded no torpedo sinkings, though she sank a trawler with gunfire 8 August north-east of Luzon, Philippines in position 19°50'N, 119°58'E. She returned to Midway 12 September 1944. The veteran submarine departed 5 October 1944 for her 11th war patrol, in the ocean approaches to Tokyo. Sighting a 5-ship convoy 7 November, she fired 4 torpedoes and sank both oiler Koto Maru and transport Kiri Maru 8.