Flying Fish's eighth war patrol, the first to be commanded by Lieutenant Commander R. D. Risser, between Taiwan and the
China coast from 30 November 1943 to 28 January 1944, found her sinking the passenger/cargo ship
Ginyo Maru (8613 tons) laden with 6880 tons of maize, 600 tons of rice, 50 tons of beans, and 195 passengers on 16 December, taking 66 crewmen, 3 IJN gunners, and 118 passengers to the bottom, and fleet tanker Kyuei Maru (10,171 tons – entering service on 6 September 1943.) from
convoy Hi-27 on 27 December. Her refit and retraining between patrols were held once more at Pearl Harbor.
Flying Fish sailed for her ninth war patrol 22 February for the waters off
Iwo Jima. On 12 March, she sent the merchantman
Taijin Maru (1924 tons) to the bottom, then closed the
Okinawa shore and attacked a convoy in the early morning darkness of 16 March. The passenger/cargo ship
Anzan Maru (5493 tons) was sunk and the tanker
Teikon Maru (ex-German
Winnetou), was damaged in this attack. Pressing on with her chase for six hours in the hope of finishing off the tanker, the submarine was detected and held down by aircraft and destroyers while the tanker escaped. On the afternoon of 31 March,
Flying Fish was attacked by a Japanese submarine, whose torpedoes she skillfully evaded. Bound for
Majuro at the close of her patrol, on April Fool's Day 1944, the submarine torpedoed and sank the freighter
Minami Maru (2398 tons – formally the Norwegian
Solviken). at
Kitadaitōjima.
Flying Fish closed out her patrol and arrived at Majuro 11 April 1944. Clearing Majuro harbor 4 May,
Flying Fish sailed for her tenth war patrol, coordinated with the assault on the
Marianas scheduled to open the next month. First she covered shipping lanes between
Ulithi,
Yap, and
Palau, coming under severe attack after one of her torpedoes exploded just outside the tubes on the night of 24 – 25 May when she was detected while attacking a four-ship convoy. At dawn, however, she had got back into position to sink the Japanese troop transport
Taito Maru (4466 tons) loaded with 5,300 aviation gasoline cans, 2,500m3 of arms and 500-tons of cement, and the passenger/cargo ship
Osaka Maru (3740 tons). The
Osaka Maru was also out of Saipan bound for Palau in the same convoy, carrying 824 passengers and materials for the war effort. 97 passengers and all of the cargo went down with the ship. Along with other American submarines, she then headed to take up a patrol station between the Palaus and
San Bernardino Strait, from which she could scout any movement by the enemy fleet out of its base at
Tawi in the
Sulus while the
Marines were landed on
Saipan. On 15 June, the day of the invasion,
Flying Fish spotted a Japanese carrier force emerging from San Bernardino Strait bound eastward. Her prompt report of this movement enabled a sister submarine, , to sink the carrier
Shōkaku four days later while American carrier aircraft broke the back of Japanese naval aviation in the
Battle of the Philippine Sea.
Flying Fish remained on her scouting station until 23 June, then sailed for
Manus and Brisbane, arriving there 5 July. == Eleventh war patrol, October – November 1944 ==