Japanese minesweeper W-101 (1943)

On 15 November 1944, she departed Moji, Kitakyūshū destined for Miri, Borneo with Type C escort ship CD-61,[6] Type D escort ship CD-134, and No.1-class auxiliary submarine chasers Cha-156 and Cha-157 escorting convoy MI-27 consisting of four tankers (Awagawa Maru, Kyokuun Maru, Osakasan Maru, and Enkei Maru) and six transport/cargo ships (Edogawa Maru, Shoho Maru, Matsuura Maru, Seisho Maru, Koshu Maru, and Chinkai Maru).[3] Enkei Maru and Kyokuun Maru developed mechanical problems and were forced to return to Moji.[3] The convoy was running parallel to Convoy Hi-81 which had left Imari on 14 November 1944 destined for Formosa to benefit from air cover provided by HI-81's escort carrier Shin'yō which was carrying fourteen Nakajima B5N "Kate" torpedo bombers of the 931st Air Squadron, Saeki Naval Air Station.[7] The two convoys converged together at times.[7]

On 17 November 1944, in the Yellow Sea off Cheju Island, MI-27 was spotted by US submarines Sunfish and Peto which were operating in a wolfpack with Spadefish.[3] Sunfish torpedoed and damaged both Edogawa Maru and Seisho Maru while Peto torpedoed and sank Osakasan Maru (killing 142).[3] Nearby, Spadefish spotted Shin'yō of HI-81 and fired six torpedoes four of which hit causing the carrier to burst into flames and sink (killing 1,130).[7] W-101 and CD-61 were unattached from MI-27 to pick up survivors.[7] On 18 November 1944, Sunfish torpedoed and sank the damaged Seisho Maru (killing 448) and the damaged Edogawa Maru (killing 2,083); while Peto torpedoed and sank Chinkai Maru (killing 39).[3] After losing four of the eight ships being escorted, the remainder of convoy MI-27 arrived at Sijiao Island on 19 November 1944.[3]

On 30 November 1944, W-101 departed Takao for Manila escorting landing craft depot ships Shinshū Maru and Kibitsu Maru along with escorts Tsushima, the Ukuru-class escort ship Daito, and four Type D escort ships (CD-14, CD-16, CD-46, and CD-134). The convoy diverted and disembarked its troops at San Fernando, Luzon due to enemy air attacks at Manila.[3]

On 29 December 1944, she joined convoy HI-85 in the South China Sea consisting of the light cruiser Kashii, two Ukuru-class escort ships (Ukuru and Daito), and three Type C escort ships (CD-23, CD-27, CD-51) in escorting nine tankers (Enkei Maru, Yamazawa Maru, Engen Maru, Encho Maru, Daigyo Maru, Otususan Maru, Fuei Maru, Oei Maru, Seria Maru) and one cargo ship (Shinyu Maru).[3] After several unsuccessful attacks by B-24 Liberator bombers, the convoy arrived at Cap Saint-Jacques on 4 January 1945.[3]

On 11 January 1945, W-101 along with CD-35, CD-43, patrol boat No. 103, and subchaser CH-31 left Cap Saint Jacques escorting convoy SATA-05 consisting of two transports (Kensei Maru, Toyo Maru), a No.101-class landing ship (T-149), and three tankers (Ayayuki Maru, Koshin Maru, Eihi Maru)[3] (T-149 was unable to handle the heavy seas and returned to Cap St Jacques).[3] On 12 January 1945, off Cap Padaran (south of Phan Rang–Tháp Chàm) in the South China Sea (11°10′N 108°55′E), W-101 was attacked and sunk by aircraft from Vice Admiral John S. McCain, Sr.'s Task Force 38 that had entered the South China Sea to raid Japanese shipping.[8] All the other ships of SATA-05 (excluding T-149) were attacked and sunk nearby.[3] W-101 was struck from the Navy List on 10 March 1945.[3]