Tateyama Air Field (館山航空基地 (Tateyama Kōkūkichi))

Tateyama Air Base is located in Tateyama, Chiba Prefecture, at the southern tip of the Bōsō Peninsula. The Imperial Japanese Navy Air Service established the facility in 1930 as part of the Yokosuka Naval District. During the Pacific War, it hosted the Tateyama Naval Air Group, which operated Mitsubishi G3M bombers, Mitsubishi A5M fighters, Nakajima B5N torpedo bombers, and Kyūshū Q1W anti-submarine patrol aircraft. The base also served as the site for the Imperial Japanese Navy Land Forces artillery school. During the final stages of the conflict, the installation functioned as a base for kamikaze aircraft and provided defense for the entrance to Tokyo Bay. Following the surrender of Japan, the United States Army First Cavalry Division occupied the field until its return to the Japanese government in 1953. It was assigned to the Safety Security Force, the predecessor of the Japan Maritime Self-Defense Force (JMSDF).

The JMSDF operates the installation as a heliport, supporting rotary-wing operations across Japan, including at Haneda, Ōminato, Maizuru, and Iwo Jima. It has served as the headquarters for Fleet Air Wing 21 since 1961. Resident units include the 21st Fleet Air Squadron, which operates squadrons of Mitsubishi SH-60J/K helicopters specialized in anti-submarine warfare. The base also hosts a flight of Mitsubishi UH-60J helicopters configured for air ambulance services to the Izu Islands. Infrastructure is restricted to rotary-wing aviation; fixed-wing aircraft associated with the base utilize the nearby Kisarazu airfield.