5 April 1942, The Indian Ocean - Across the wide expanse of the eastern Indian Ocean at land bases, seaplane anchorages, and onboard aircraft carriers, flight operations began early in the morning on 5 April 1942 for both the British and the Japanese. The search aircraft of the Kido Butai were first off the mark with eight planes launching at 0430 in the morning to cover a 120 degree search arc to the west of Nagumo's carriers. The heavy cruisers Tone and Chikuma each launched two E13A Jake floatplanes and the carriers Shokaku and Zuikaku each launched one B5N Kate torpedo bomber to fly 300 mile search vectors to the southwest of the Kido Butai. The battleships Kongo and Haruna each launched one E8N Dave floatplane to search 200 mile vectors to the northwest of the Kido Butai, the area considered to be the least likely to contain heavy units of the Eastern Fleet. Additionally, the Tone and Chikuma as well as the battleships Hiei and Kirishima each launched one Dave floatplane for the morning's anti-submarine patrols. At 0500, Nagumo's carriers became bustling hives of activity as all five carriers spotted and launched a shotai of three A6M Zeroes for the combat air patrol. Once the Zeroes were in the air the deck crews began spotting the aircraft for the strike against Colombo. Akagi, Hiryu, and Soryu each contributed 18 B5N torpedo bombers armed with 800 kg armor piercing bombs instead of torpedoes while Shokaku and Zuikaku added 18 D3A Val dive bombers from each carrier. The strike force was covered by 36 Zeroes, nine each from Akagi, Soryu, Hiryu, and Shokaku. At 0600 Nagumo's carriers turned into the wind and began launching aircraft. By 0620 all 126 aircraft under the command of Commander Fuchida Mitsuo who led the attack on Pearl Harbor were in the air and headed north on the 200 mile flight to Colombo.
A similar story, albeit on a much smaller scale played out at Port Blair and with the Malay Force. At 0500, six H6Ks launched from the harbor at Port Blair under the watchful eye of a shotai of Zeroes from Mingaladon. Two would head northwest to cover search arcs between Visakhapatnam and Calcutta to help sniff out British convoys for the Malay Force while four were tasked to fly deep into the Indian Ocean south of Ceylon on long search legs of almost 1200 miles to assist in providing reconnaissance for the Kido Butai. The Malay Force itself was still following a fairly easy routine. It would not be in position to attack British merchant shipping along the Indian coast until early the next morning so at this time flight operations consisted of keeping a shotai of A5M Claudes above the task force on combat air patrol while using the E8N Daves from the heavy cruisers for anti-submarine patrols.
Finally, at Mingaladon airfield, 12 of the 18 G3M Nell bombers that had arrived from Bangkok during the afternoon of 4 April along with six Zeroes were preparing for a strike against the British airbase at Akyab in Burma. The recent heavy bomber raids against Port Blair convinced Japanese commanders that Akyab was still an active base that needed to suppressed. The small strike force launched at 0630.