YSFlight is a free, open-source multi-platform flight simulator, developed and published by Soji Yamakawa since 1999.

[contradictory] Development of YSFlight began in 1998 as a solo project by Soji Yamakawa.

Initially designed to be run by lower-end computers, the flight simulator began to implement more updated graphical features with its 2015 release.

On August 19, 2022, Yamakawa published YSFlight's source code and assets to GitHub under the BSD-3-Clause license, while stating that he intends to continue the simulator's development.

[4] It allows for to YSFlight clients to join a multiplayer server.