A seat assembly for a personal watercraft, comprises a seat portion. A support portion is connected to the seat portion, and is adapted to connect the seat portion to the personal watercraft in a seating position of the seat assembly, in which a rider of the personal watercraft is in a seated position on the personal watercraft. A storable configuration is provided between the seat portion and the support portion, for the seat assembly to be displaceable while being connected to the personal watercraft between the seating position and a collapsed position in which the seat assembly is adapted to be stored in the personal watercraft, such that the rider of the personal watercraft can be in a standing or kneeling position on the personal watercraft.