Focused on frontal equipment and tactics, the Imperial Navy tends to underestimate information. However, they are not foolish enough to overlook the full-scale deployment of the Pacific Fleet. Reports from the I-boats (submarines) on patrol and interception of enemy communications already revealed that the main force of the Pacific Fleet had taken positions off Brisbane. The Pacific Fleet likely planned to coordinate with the base air force deployed around Brisbane. Anticipating this, the carrier-based aircraft were configured with an increased ratio of fighters. Emphasizing the acquisition and maintenance of air superiority over the destruction of enemy ships, the formation prioritized gaining control of the airspace within the range of enemy land-based aircraft.
First Fleet
- Battleships Yamato, Musashi, Shinano, Kii, Hiei, Kirishima, Kongō, Haruna
- Heavy cruisers Kumano, Suzuya, Mogami, Mikuma
- Heavy cruiser Aoba
- Destroyers Yukikaze, Hatsukaze, Amatsukaze, Tokitsukaze, Urakaze, Isokaze, Hamakaze, Tanikaze
- Heavy cruiser Kinugasa
- Destroyers Hagikaze, Maikaze, Nowaki, Arashi, Akigumo, Yūgumo, Makigumo, Kazagumo
Second Fleet
- Battleships Nagato, Mutsu, Ise, Hyūga, Yamashiro, Fusō
- Heavy cruisers Atago, Takao, Maya, Myōkō, Haguro, Nachi
- Heavy cruiser Furutaka
- Destroyers Kuroshio, Oyashio, Hayashio, Natsushio, Kagerō, Shiranui, Kasumi, Arare
- Heavy cruiser Kako
- Destroyers Asagumo, Yamagumo, Natsugumo, Minegumo, Asashio, Ōshio, Michishio, Arashio
Third Fleet
- Kaga (36 × A6Ms, 45 × B5Ns)
- Akagi (36 × A6Ms, 27 × B5Ns)
- Ryūjō (24 × A6Ms, 9 × B5Ns)
- Ryūhō (24 × A6Ms, 3 × B5Ns)
- Heavy cruiser Tone
- Destroyers Umikaze, Yamakaze, Kawakaze, Suzukaze, Murasame, Yūdachi, Harusame, Samidare
Fourth Fleet
- Sōryū (36 × A6Ms, 21 × B5Ns)
- Hiryū (36 × A6Ms, 21 × B5Ns)
- Zuihō (24 × A6Ms, 3 × B5Ns)
- Shōhō (24 × A6Ms, 3 × B5Ns)
- Heavy cruiser Chikuma
- Destroyers Shiratsuyu, Shigure, Hatsuharu, Nenohi, Wakaba, Hatsushimo, Ariake, Yūgure
The fleet consisted of 14 battleships, 8 carriers, 16 heavy cruisers, and 48 destroyers. Overall command was in the hands of Vice Admiral Nobutake Kondō, the commander of the Second Fleet. Vice Admiral Shirō Takasu and Vice Admiral Jisaburō Ozawa commanded the First Fleet and Third Fleet, respectively, just like in the Battle of the Marshall Islands.
Unlike the previous Battle of the Marshall Islands, a new Fourth Fleet was established due to the increase in carriers. Having eight carriers in one fleet still seemed excessive and if they got exposed to a large number of enemy aerial attacks, they would be overwhelmed. The division of the carrier force into two fleets, which meant that more escort ships such as cruisers and destroyers would be needed than before, did not sit well with the gunnery faction, but they still understood the importance of gaining air superiority in a fleet battle, so they reluctantly accepted it. Vice Admiral Torao Kuwabara assumed the position of commander in the newly formed Fourth Fleet.
The eight carriers carried the new models of A6Ms and B5Ns. Despite enhanced bulletproof equipment, both models exhibited an improved maximum speed of 1.300 horsepower from the Kinsei 50 engine, with increased acceleration and climbing capabilities for the Zero. The previously criticized armament of the Zero, featuring 7,7 mm machine guns, was upgraded to four 12,7 mm machine guns, similar to the Army's Ho-103 – essentially a copy of the Browning machine gun. In exchange for supporting the Imperial Navy in the Indian Ocean Operation to cut off the Chongqing route, the Imperial Army provided technical assistance, including the supply of the Ki-46 recon planes.
The two surface strike forces, along with the two mobile forces, hurried towards Brisbane while rigorously maintaining anti-submarine vigilance. Their stated goal was the destruction of the submarine base in Brisbane, but their actual objective was the annihilation of the Pacific Fleet and the complete destruction of the city of Brisbane itself.
The US Navy which continued to deploy new ships and cutting-edge aircraft was expected to surpass the Imperial Navy's strength by the end of this year. The disparity would only increase in the following years. Therefore, it was crucial to deliver a severe blow to the US Navy, forcing Australia to withdraw from the war before this happened.