November 1944. On that date, she surfaced in the Philippine Sea east of Manila at around 01:00 and drew the attention of a United States Navy destroyer — probably , later joined by the destroyer — which pursued her for 38 hours. With her crew issued special vials containing chemical compounds to minimize the carbon dioxide content in her interior, I-53 had to descend to a depth of before she finally managed to break contact. She returned to Kure on 22 November 1944. First kaiten mission While I-53 was at Kure, shipyard workers completed her conversion to carry kaitens. On 8 December 1944, she was assigned to the Kongo ("Steel") Kaiten Group along with the submarines I-36, , , I-56, and for an attack scheduled for dawn on 11 January 1945 on five different U.S. anchorages in widely separated locations; the date of the attack later was postponed to 12 January 1945. On 19 December 1944 she took part in exercises with the other submarines of the Kongo group. I-53 and I-58 arrived at Otsujima on 28 December 1944, where they embarked their kaitens and the kaiten pilots. At 10:00 on 30 December 1944, I-53 got underway in company with I-36 and I-58 bound for their target, the U.S. fleet anchorage at Kossol Roads in the Palau Islands. She surfaced off Kossol Roads at 07:00 on 12 January 1945 and launched her kaitens. One exploded soon after launch, and another never started its engine. The other two launched without incident. I-53 submerged to await developments and heard two explosions from the direction of Kossol Roads about 80 minutes after launching her kaitens. Japanese observers on a nearby island reported that two kaitens had scored hits on Allied ships in the anchorage and I-53 was credited with sinking two transports, although postwar analysis could confirm no sinkings. I-53 then surfaced to inspect the kaiten which had not started its engine and discovered that its pilot had been rendered unconscious by fumes from its fuel. I-53 returned to Kure on 26 January 1945 for repairs and an overhaul. Second kaiten mission On 27 March 1945, I-53 was assigned to the Tatara Kaiten Group along with I-44, I-47, I-56, and I-58 for an attack on American ships off Okinawa, with I-47 serving as the group's flagship. She got underway from Kure on the afternoon of 30 March 1945 bound for Hikari, where she