There are three major classifications of diving – diving in caves, dive in open water and cave diving.
The diving in open water is the starting point for all divers and is one in which the linear access to the surface is always available – in other words, just swim up and the diver can take the head of water. The sun is always visible in this mode.
In diving in caves, on the other hand, the diver is exploring natural caves and permanent, with their roofs, but with an entry and sunlight visible. Both the open water diving and diving in caves are considered recreational activities that require licensing and training of amateur level. Divers such arrangements generally limit their dives to 40 meters.
The cave diving differs from the other two methods because it is a form of technical diving, and not recreation. It requires specialized equipment, several years of training and qualification. Professionals emphasize the continuing need for equipment and physical fitness of first line.