 Formidable sailed on 17 February to join the Eastern Fleet in the Indian Ocean, escorting a convoy to Freetown, Sierra Leone, en route. One of her passengers on the voyage was Admiral Sir James Somerville, about to take up his appointment as Commander-in-Chief of the Eastern Fleet. The ship arrived at Colombo, Ceylon, on 24 March and Somerville hoisted his flag aboard the battleship Warspite that same day. Two days after Formidable's arrival, the Japanese First Air Fleet departed from Celebes (Sulawesi) in the Dutch East Indies to attack British forces in the Indian Ocean. Somerville was notified that the Japanese were planning on attacking Ceylon on 28 March and ordered his fleet to assemble southeast of the island on 30 March to intercept them. Force A, consisting of Formidable, her sister Indomitable and Warspite, was ordered to Addu Atoll to refuel on 3 April after the Japanese failed to attack as the British expected. A Royal Air Force Consolidated Catalina flying boat spotted them within range of Ceylon just three and a half hours after Force A arrived at the atoll on 4 April. Too far away to intercept them before they could attack Ceylon, Force A departed about eleven hours after arrival on a course that Somerville thought would allow him to attack by night while avoiding detection during the day. One of Indomitable's Albacores spotted some of the Japanese carriers just before nightfall on 5 April, after the Japanese attacked Colombo, but further searches failed to locate them until 8 April when the Japanese were one day away from their intended target, Trincomalee, and still too far away to intercept. Force A refuelled at Addu Atoll on 9 April and was then ordered to Bombay to calm fears of a Japanese attack on India's west coast.
