I-371 was laid down on 22 March 1944 by Mitsubishi at Kobe, Japan, with the name Submarine No. 5471.[1] She was launched on 21 July 1944 and renamed I-371 that day.[1] She was completed and commissioned on 2 October 1944.[1]
Upon commissioning, I-371 was attached to the Sasebo Naval District and was assigned to Submarine Squadron 11 for workups.[1] She was reassigned to Submarine Squadron 7 on 6 December 1944.[1] During December 1944, she moved from the Seto Inland Sea to Yokosuka and began a 20-day period of workups from there.[1]
On 30 December 1944, I-371 departed Yokosuka bound for Truk and Mereyon Island at Woleai in the Caroline Islands on her first transport mission, carrying a cargo of 50 metric tons of food and mail, as well as aviation gasoline, spare parts, and ammunition for the Truk-based 171st Naval Air Group, which the aviators required to resume flights by Nakajima C6N1 Saiun ("Iridescent Cloud"; Allied reporting name "Myrt") reconnaissance aircraft over the American fleet anchorage at Ulithi Atoll.[1] She arrived at Truk on 18 January 1945 and unloaded the portion of her cargo destined for Truk.[1] During her stay, an Aichi E13A1 (Allied reporting name "Jake") floatplane arrived from Mereyon on 20 January 1945 with a coded message about I-371′s planned arrival there.[1]
On 22 January 1945 I-371 got underway from Truk bound for Mereyon, which she reached at around 22:00 on 25 January 1945.[1] She unloaded 50 metric tons of food and mail, allowing an increase in the daily ration of rice for each member of the starving Japanese garrison on Mereyon from 5oz7oz.[1] She completed unloading her cargo at 03:00 on 26 January 1945 and headed back to Truk, where she arrived on 28 January 1945.[1] She embarked some passengers and put back to sea, bound for Japan, with an estimated arrival date of 21 February 1945.[1] She never arrived.[1]
The circumstances of I-371′s loss are not clear. At 11:13 on 24 February 1945, the United States Navy submarine was operating in the Bungo Strait off the coast of Japan when she detected a surfaced submarine on radar at a range of 5000yd.[1] Lagarto sank the submarine at 32.6667°N 165°W.[1] Her victim probably was I-371, although I-371 would have been running three days behind schedule to be in that location at that time.[1] Other accounts credit the destroyer with sinking I-371 off Okinawa on 23 March 1945, but that was 11 days after the Japanese had declared I-371 missing, and it is more likely that Haggard sank the submarine .[1]
On 12 March 1945, the Imperial Japanese Navy declared to be presumed lost in the vicinity of Truk along with all 84 crew and passengers on board.[1] She was stricken from the Navy list on 10 April 1945.[1]