To provide a seat for a jet ski which can sufficiently absorb impacts during running.

For this seat 10 for a jet ski 200, a cushion material is arranged on a bottom plate, and the cushion material is covered with a skin material. The seat 10 is equipped with an air cushion 20 which is arranged under the seat surface, an air pump 40 which feeds gas into the air cushion 20, and a cylinder 30 which communicates with the inside of the air cushion 20 and absorbs impacts.