Strictly speaking, Jet Ski is the trademarked name of a personal water craft (PWC) produced by the Kawasaki Motor Company, but the term "jet ski" has become a generic name for all types of personal watercraft. While Kawasaki first marketed a Jet Ski in 1973, a smaller company called Bombadier actually created a workable personal watercraft in the late 1960s. Years after the Kawasaki Jet Ski became a household name, Bombadier came back with the Sea Doo and managed to make a dent in the personal water craft marketplace. Another popular PWC model is called a WaveRunner.

A jet ski is part water skiing device and part speedboat, with a definite hint of motorcycle during operation. Instead of the traditional propeller or screw motor, a jet ski uses an enclosed gas-powered motor to literally push water out in a jet stream. The jet ski operator straddles a central platform and assumes a shock-absorbing posture with knees slightly bent. The motor is electronically started with a toggle switch located in a column in front of the driver. All jet ski models should also have a dead man's switch -- a connection between the driver and ignition system which should kill the motor instantly if the driver falls off.

Much like a motorcycle, acceleration in a jet ski is provided by a hand-powered throttle located on the right-side grip. By twisting the throttle, the driver can increase power to the motor. Steering a jet ski requires a combination of pointing the front-mounted grips and maneuvering the body. Unlike a street motorcycle, a jet ski often requires significant acceleration to accomplish sharp turns in the water.

The use of a jet ski or any other personal watercraft is often limited by state or local laws. There may be helmet, age and flotation device regulations as well, so jet ski owners should always check before putting their PWCs in unfamiliar waters. Speedboats and other large recreational watercraft often cannot avoid collisions with smaller jet skis. Irresponsible actions on a jet ski can also lead to dangerous encounters with swimmers and traditional water skiiers. There is also a temptation for some jet ski drivers to deliberately drive through the wake of larger boats.

In the hands of an experienced driver, a jet ski can provide hours of excitement. Some PWCs can accommodate two or more riders, and have enough towing power for innertubes or water skis. Jet skis are also popular with ocean-based lifeguards and rescue squads.