She served in World War II, and took part in operations supporting the attack on Pearl Harbor, the Battle of Midway, and the Aleutian Islands campaign.

[2] As the Imperial Japanese Navy began to deploy in preparation for the impending conflict in the Pacific, I-71 was assigned to Operation Z, the planned Japanese attack on Pearl Harbor,[3] as a unit of Submarine Division 20 in Submarine Squadron 3, which in turn was assigned to the 6th Fleet′s Advanced Expeditionary Force.

On 7 December 1941, the submarines of Submarine Squadron 3 operated south of Oahu to intercept any U.S. ships which attempted to sortie from Pearl Harbor during or after the Japanese attack there that day that brought Japan and the United States into World War II.

[2] At dawn on 28 January 1942 she was in Alenuihaha Channel off Maui's Hana Coast 30 nautical miles (56 km; 35 mi) north of ʻUpolu Point, the northernmost point on the island of Hawaii, when she attacked a three-ship convoy on a voyage from Kahului, Maui, to Hilo, Hawaii, consisting of the 622-ton United States Army Transport USAT General Royal T. Frank, the small cargo ship Kalae with a barge in tow, and their escort, the destroyer minesweeper USS Trever (DMS-16).

[2] After Task Force 11 lost the element of surprise, however, it withdrew, and I-71 was diverted to a patrol area east of Wake Island.

[2] On 24 May 1942, I-171 departed Kwajalein to participate in Operation MI, the planned Japanese invasion of Midway Atoll.

[2] Her first task was to support a preliminary phase of the Midway operation, Operation K-2, which called for the submarines I-121 and I-123 to refuel two Kawanishi H8K (Allied reporting name "Emily") flying boats at the French Frigate Shoals in the Northwest Hawaiian Islands so that the two aircraft could make a reconnaissance flight over Pearl Harbor,[4][5] while the submarine I-122 patrolled south of Pearl Harbor to rescue the crews of the aircraft if they were shot down and I-171 operated east of the French Frigate Shoals to provide a radio beacon for the planes.

[2] After the completion of her overhaul, I-171 spent the winter, spring, and much of the summer of 1943 involved in the Aleutian Islands campaign, which had begun in mid-1942.

[2] After refueling from the oiler Teiyō Maru on 20 March 1943,[2] she departed Paramushiro on her fifth war patrol, operating in the Bering Sea in the vicinity of 52°55′N 174°00′E / 52.917°N 174.000°E / 52.917; 174.000 as part of a submarine scouting line.

On 21 May 1943, with the situation on Attu deteriorating — ultimately the battle there ended on 30 May 1943 with the annihilation of the Japanese garrison — the Japanese Imperial General Headquarters decided to evacuate the isolated garrison on Kiska,[2] and on the same day I-171 departed Yokosuka to begin her sixth war patrol, bound for Kiska.

[2] She departed Truk on 7 October 1943 with the commander of Submarine Division 12, Captain Hajime Kobayashi, on board to begin her eighth war patrol, tasked with conducting a reconnaissance of the New Hebrides.

[2] While she was at sea, Kobayashi received orders from the commander of the 6th Fleet, Vice Admiral Takeo Takagi, to take temporary command of I-171 and the submarines I-21 and I-32 and intercept a convoy of six U.S. Navy fleet oilers that the submarine I-36 had sighted south of the Hawaiian Islands.

[2] However, a Kawanishi H8K ("Emily") flying boat dispatched from Jaluit to find the convoy failed to locate it.

[2] While at Truk during December 1943 and early January 1944, I-169 took torpedoes, ammunition, and stores aboard from the auxiliary submarine tender Heian Maru.

[2] On 12 March 1944, the Japanese declared her to be presumed lost off Buka Island with the loss of all 91 men on board.

On 14 March 1944, U.S. Navy codebreakers intercepted and decrypted a message from the commander of the Southeastern Area Submarine Force which read, "I-171 departed Rabaul January 30, arrived Buka Feb. 2 [blurred number might be 1 or might be 2].