Hasegawa 1/72 G3M2/3 Type 96 (Nell)

The G3M flew for first time in 1935, taking off from a Nagasaki airfield belonging to Mitsubishi Heavy Industries and landing at Haneda Airport on the outskirts of Tokyo. The G3M first saw combat in Japan's expansionist campaigns on the Chinese mainland in what became known as the Second Sino-Japanese War, where the G3M was able to exploit its long-range capability when, during August–November 1937, the "1st Rengo Kokutai" (a special unit) was established, operating alongside the "Kanoya" and "Kizarazu Kokutai" based in Taipei, Formosa, Omura, Kyūshū and Jeju Island. On August 14 of that same year forty-two "Nells" and seven Hiro G2H1s, escorted by 12 Nakajima A4Ns and 12 Mitsubishi A5Ms of the "2nd Rengo Kokutai" (a unit consisting of the 12th and 13th Kokutai), departed from their bases to cross the East China Sea, for the bombing of Hangchow and Kwanteh, and performed amongst others actions of terror bombing in coastal and inland targets in China, including the bombing during the Battle of Shanghai and Nanjing. Later, from bases in occupied Chinese territories, it took part in the strategic carpet bombing of the Chinese heartland, its combat range being sufficient to cover the elongated distances involved. Most notably, it was involved in the round-the-clock Bombing of Chongqing.

When the Pacific War erupted in 1941, after the Bombing of Pearl Harbor, the G3M was by this time considered to be antiquated but still 3 front-line units (the 22nd to 24th Koku Sentai) were operating a total of 204 G3M2s in four Kokutai (Naval Air Corps) in the central Pacific and of these 54 aircraft from the Takao Kokutai were deployed from Formosa in the opening of the Battle of the Philippines. On the 8th of December 1941, (7th across the International Date Line), G3Ms from the Mihoro Kokutai struck Singapore City from bases in occupied Vietnam as one of many air raids during the Battle of Singapore, resulting in thousands of British and Asiatic civilians dead. Wake Island was similarly bombed by G3Ms from the Chitose Kokutai on the first day of the war, with both civilian and US Navy infrastructure being heavily damaged on the ground.

The G3M was famous for taking part in the sinking of two British battleships with the more advanced Mitsubishi G4M "Betty", on 10 December 1941. "Nells" from the Genzan Kokutai provided important support during the attack on the HMS Prince of Wales and Repulse (Force Z) near the Malayan coast. Prince of Wales and Repulse were the first two battleships ships ever sunk exclusively by air attack while at sea during war.

A G3M of the Mihoro Air Group was involved in a dogfight with a Consolidated PBY Catalina flying boat of No. 205 Squadron RAF near the Anambas Islands on 25 December 1941, in which the Catalina was shot down.

The attack on Darwin, Australia on February 19, 1942, by 188 Japanese aircraft, included 27 G3Ms of the 1. Kokutai (1st Air Group) based at Ambon, in the Dutch East Indies (Indonesia). The "Nells" attacked alongside 27 G4Ms. These bombers followed an 81-strong first wave of Mitsubishi A6M Zero fighters, Aichi D3A dive bombers and Nakajima B5N torpedo bombers.

From 1943, the majority of "Nells" served as coastal patrol aircraft,  glider tugs, aircrew and paratroop trainers and for transporting high-ranking officers and VIPs between metropolitan islands, occupied territories and combat fronts until the end of the war.

The difference between the G3M2 and G3M3 is that the latter had more powerful engines and was built solely by Nakajima. Externally, they were identical.