A personal water craft (PWC), also called water scooter, jetski, and comically a boatercycle, is a recreational watercraft that the rider sits or stands on, rather than inside of, as in a boat. PWCs have two style categories. The first and most popular being a "sit down" or "couch", where the rider uses the watercraft mainly sitting down and typically holds two or more people. The second style is a "stand up", where the rider uses the watercraft standing up. The stand up styles are built for one rider and is used more for doing tricks, racing, and are used in competitions. Both styles have an inboard engine driving a pump jet that has a screw-shaped impeller to create thrust for propulsion and steering. They are often referred by the trademarked brand names Jet Ski, WaveRunner, or . Most are designed for two or three people, though four-passenger models exist.
The United States Coast Guard defines a personal watercraft, amongst other criteria, as a jet drive boat less than 13 feet (4 m) in length, in order to exclude from that definition more conventional sized jet boats. There is a wide variety of "jet boats" many of which exceed 30–40 feet (9–12 m) in length.
Water scooters - as they were originally termed - were first developed in the United Kingdom and Europe in the mid-1950s, with models such as the British 200cc propellor-driven Vincent Amanda, and the German Wave Roller. Two thousand Vincent Amandas were exported Australia, Asia, Europe and the United States. In the 1960s, the idea was developed further by Clayton Jacobson II of Byron Bay, Australia. Originally a motocross enthusiast, Jacobson's idea was designed in the mid-1960s, powered by an internal pump-jet rather than an outboard motor, made of all aluminum, and had a fixed, upright handle. Jacobson eventually quit his job in banking to devote himself to developing the idea, and had a working prototype by 1965. It differed slightly from modern personal watercraft but had definite similarities. He completed a second prototype a year later made of fiberglass.