Mitsubishi Ki-21-II-Ko(a), of Hamamatsu Army Flying School, Japanese Army Air Force, based at Hamamatsu Air Base, Shizuoka Prefecture, Japan, 1939.
Mitsubishi Ki-21-Ib, of 2nd Chutai, 7th Kokutai, Japanese Army Air Force, based in Malaysia, 1942.
Mitsubishi Ki-21-II-Ko(a), of 2nd Chutai, Hamamatsu Army Flying School, Japanese Army Air Force, based at Hamamatsu Air Base, Shizuoka Prefecture, Japan, 1943.
Mitsubishi Ki-21-II-Ko(a) of 3 Koku gun, Japanese Army Air Force, based at Sembawang, Singapore, early, 1945.
Mitsubishi Ki-21-I (a), of 2nd Chutai, 60th Hiko Sentai, Japanese Army Air Force, used in action over Manchuria China, 1939.
Mitsubishi Ki-21-II Ko(a), of 1st Chutai, 81st Sentai, Japanese Army Air Force, based at Lakunai Air Base, East New Britain, 1943.
Mitsubishi Ki-21-II Ko(a), of 22nd Hikoshidan, Japanese Army Air Force, based in Republic of Formosa, 1945.
Mitsubishi Ki-21-II Ko(a), of 1st Chutai, 62nd Sentai, Japanese Army Air Force, based in Thailand, 1942. [Ki-21-Ia Ki-21-Ib "Sally"]