The Japanese Navy employed two land-based bombers for long-range naval support, the first of these was the Mitsubishi G3M 'Nell', Japan's first modern bomber which entered service as far back as 1936. Designed by a team led by Prof. Kiro Honho under the recommendation of the then-unknown Admiral Yamamoto, the G3M was fairly successful during the first years of the conflict and best known for its participation in the sinking of the British battleship HMS Prince Of Wales and battlecruiser HMS Repulse off Singapore three days after Pearl Harbor (the aircraft involved were Saigon-based G3Ms of the Genzan Naval Air Group), the first battleships to be sunk by aircraft while at sea. Despite the advantage of tremendous range (G3Ms performed the world's first trans-oceanic raids against China in 1937), the 'Nell' was very poorly protected making it easy prey for Allied fighters and as such, began to be relegated to second-hand duties such as training, transport and radar-equipped maritime patrol after 1942.

First flown in July 1935, production G3M1s entered service in mid-1936 and saw action in the war against China. Subsequent improvements resulted in the G3M2 with more powerful Kinsei 42/45 engines and were the type used to sink the British warships mentioned while the G3M3, by far the best variant produced, featured a Kinsei 51 engine and an increased defensive armament fit as well as extended range. Armed transport conversions were known by the designations L3Y-1 and L3Y-2 'Tina' and corresponded to the G3M1 and G3M2 respectively.