A personal watercraft (PWC) is disclosed that is convertible between a stand-up type watercraft, and at least one of a straddle-type watercraft, a sit-down type watercraft or a kart-type position watercraft. The PWC includes a hull supporting a power source, and a deck, the deck supporting a steering handle support assembly. A kart-type seat assembly is removably supported by the deck, such that the seat assembly can be selectively removed by the user so that the personal watercraft can be operated with and without the kart-type seat assembly.