First, you must have advanced open-water certification from any of the major scuba certification agencies as a pre-requisite to training as a cavern diver. While a Rescue Diver course is not required, the rigors of Rescue Diving may give you a better idea of the rigors of cavern and cave diving. Also, the more dives you have — meaning, the more experience you have in many different situations — the better prepared you will be for learning about and dealing with the underwater cave environment. 50 open-water dives may not be enough for most divers, especially if many of them were in sheltered coves or lakes. You also need to become introspective and decide how you would deal with emergency situations. Has a fin ever fallen off your foot? Have you ever been entangled in a line or other object underwater? Have you ever kicked up some silt or been in a very low- or no-visibility situation? Have you ever had your mask kicked off by another diver? Have you ever run low on or out of air? How did you handle these situations? Did you ever feel panicky? Did you take steps so that that problem will never happen again? Do you take adequate care of your equipment? And… can you hold your ego in check, and end a dive because things aren’t going right?