- Daiya Seto
- 3:54.81 minute(s):second(s)
- United States (Las Vegas)
The fastest short course 400 metres individual medley swim by a male is 3 minutes 54.81 seconds, achieved by Daiya Seto (Japan) on 20 December 2019 at the International Swimming League Grand Final in Las Vegas, Nevada, USA.
Seto broke a record that had stood for nine years. He was swimming for the Energy Standard team at the ISL Grand Final.