Kayaking is the use of a kayak for moving across water.
There are many types of kayaks used in flat water and white water kayaking. The sizes and shapes vary drastically depending on what type of water to be paddled on and also what the paddler would like to do.
Kayak diving is a type of recreational diving where the divers paddle to a diving site in a kayak carrying all their gear to the place they want to dive.
Kayak fishing is fishing from a kayak.