バラバク海峡
After transiting Balabac Strait on 22 September, "Bonefish" continued on to her patrol area in the central part of the South China Sea. Three days later, the submarine attacked a convoy of eight ships, scoring three hits on a freighter before the escorts forced her to go deep to avoid a depth charge attack. "Bonefish" encountered another convoy on 27 September and launched four torpedoes at the lead ship, the largest of the five, and sank the 9,908 ton transport "Kashima Maru" and damaged the "Chihaya Maru". The escort ships pursued "Bonefish", but she was able to dive and elude her attackers. On 6 October, the boat approached a third convoy and scored hits on two heavily laden cargo vessels. Again forced to go deep to avoid the counterattack, she failed to evaluate the damage that her torpedoes had done to the targets. On 10 October, in her last action of the patrol, "Bonefish" fired a spread of four torpedoes at two ships of a convoy off Indochina, sending both the 4,212 ton cargo ship "Isuzugawa" and the 10,086 ton transport "Teibi Maru" to the bottom. On 14 October the "Bonefish" sank a Japanese sailing vessel in the Makassar Strait. "Bonefish" concluded her first war patrol back at Fremantle, Western Australia, on 21 October.