to the First Carrier Division with Shōkaku and Zuikaku and they sailed for Eniwetok Atoll on 18 September for training; a secondary objective was to be in position to intercept any attacks by American carriers in the vicinity of Wake Island and the Marshall Islands area. That day the American carriers raided the Gilbert Islands and were gone by the time the Japanese reached Eniwetok on 20 September. Japanese intelligence reports pointed to another American attack in the Wake-Marshall Islands area in mid-October and Admiral Mineichi Koga sortied the Combined Fleet, including the First Carrier Division, on 17 October. They arrived at Eniwetok two days later and waited for reports of American activity until 23 October. They then sailed for Wake Island and then returned to Truk on 26 October without encountering any American ships. Zuihōs air group was transferred to Rabaul at the beginning of November, just in time to participate in the raid on Rabaul a few days later. The fighters claimed to have shot down 25 American aircraft at the cost of eight pilots; the survivors flew back to Truk and remained ashore. On 30 November, Zuihō, together with the escort carriers and , departed Truk for Japan, escorted by four destroyers. The Americans had cracked the Japanese naval codes and positioned several submarines along their route to Yokosuka. unsuccessfully attacked Zuihō on 30 November, while torpedoed and sank Chūyō five days later with heavy loss of life. From December to May 1944, Zuihō ferried aircraft and supplies to Truk and Guam although she was reassigned to the Third Carrier Division on 29 January, together with the converted carriers and . Each of the three carriers was intended to be equipped with 21 fighters and 9 torpedo bombers, but this plan was changed on 15 February to a consolidated air group, the 653rd, that controlled the aircraft of all three carriers. While fully equipped with 18 Zero fighters, 45 Zero fighter-bombers, 18 B5Ns, and 9 Nakajima B6N "Jill" torpedo bombers by May, the air group's pilots were largely drawn from the two most recent classes of flight school graduates and lacked experience. The ship sailed for Tawi-Tawi on 11 May in the Philippines. The new base was closer to the oil wells in Borneo on which the Navy relied and also to the Palau and western Caroline Islands where the Japanese expected the next American attack. However,