Kayaks can be broken down into two types (sit-in, sit-on-top) and six basic categories (recreational, day-touring, sea, whitewater, fishing, pedal kayaks):
Sit-in – Traditional enclosed kayaks with a cockpit opening.
Sit-on-top – Open kayaks without a deck or cockpit opening; allow for freer movement.
Recreational – Generally of short to medium length and intended for calmer waters; typically feature large open cockpits and wide, stable hulls. May be sit-in or sit-on-top.
Day-Touring or Light-Touring - Generally of medium length (11 to 14 foot) and intended for intermediate waters and longer trips; typically feature a skeg or rudder, generous storage space, and a hull of average width for stability and speed. May be sit-in or sit-on-top.
Sea – Generally of greater length (over 15 feet) and intended for rough conditions and long trips; typically feature a skeg or rudder, generous storage space for longer trips or expeditions, and a narrow hull for speed and efficiency. Usually sit-in.
Whitewater – Generally of short length and intended for faster-moving water; typically feature a hull that is designed to become one with your body and ensure maneuverability. Usually sit-in.