Flier reached Pearl Harbor from New London, Connecticut on 20 December 1943 and prepared for her first war patrol, sailing on 12 January 1944. However, the submarine ran aground near Midway Island on 16 January. USS Macaw, a Chanticleer-class submarine rescue ship, attempted to pull Flier free but ran aground herself and sank. Flier was eventually saved by USS Florikan and towed to first Pearl Harbor and then to Mare Island Navy Yard for repairs. On 21 May, she sailed again for action, heading for a patrol area west of Luzon. She made her first contact on 4 June, attacking a well-escorted convoy of five merchantmen. Firing three torpedoes at each of two ships, she sent the transportHakusan Maru to the bottom and scored a hit on another ship before clearing the area to evade countermeasures.
On 13 June 1944, Flier attacked a convoy of 11 ships, cargo carriers and tankers, guarded by at least six escorts. The alert behavior of the escorts during the attack resulted in a severe counterattack on Flier before she could observe what damage she had done to the convoy. On 22 June, she began a long chase after another large convoy, scoring four hits for six torpedoes fired at two cargo ships that day, and three hits for four torpedoes launched against another cargo ship of the same convoy the next day.
On 1 February 2009, the U.S. Navy announced the discovery of
Flier near the Philippines' Balabac Strait(7°58′43.21″N117°15′23.79″E)Coordinates: 7°58′43.21″N117°15′23.79″E. The discovery of a Gato-class submarine was made during an expedition by YAP Films, based in part on information provided by a survivor of the sinking of Flier. Further research by the Naval History and Heritage Commandrevealed that no other submarine, American or Japanese, had been reported lost in that general vicinity. In addition, footage of the wreck showed a gun mount and radar antenna, both of which were similar to the same equipment seen in contemporary photographs of Flier. The ship rests in 330 ft (100 m) of water.
LT James W. Liddle, CDR John Daniel Crowley, ENS Alvin E. Jacobson
James Dello Russo, QM3; Wesley Bruce Miller, MoMM3; Earl R. Baumgart, MoMM3;
Arthur Gibson Howell, CRT(AA). Not pictured: Donald Paul Tremaine, FC2
Flier received one battle star for World War II service on her single complete war patrol, designated "Successful." She is credited with having sunk 10,380 tons of Japanese shipping.