The 21st Fighter Training Squadron (第21飛行隊, Dainiichi Hikōtai) is a squadron of the 4th Air Wing of Air Training Command of the Japan Air Self-Defense Force.

After retiring their original North American F-86F Sabres, from January 12, 1982 to December 22, 1995 the JASDF aerobatics team Blue Impulse flew Mitsubishi T-2 aircraft as part of the squadron.

During the 2011 Tōhoku earthquake and tsunami, Matsushima Air Field was flooded with seawater, and eighteen Mitsubishi F-2B's belonging to 21st Squadron, as well as other aircraft, were damaged or destroyed.

[3][4] In the aftermath of this event, the 21st was relocated to Misawa Air Base where it conducted a reduced schedule of training while both the airfield and its damaged aircraft were repaired.

A ceremony marking the 21st's return to Matsushima was held on March 28, 2016.