The Cavern Diver course offered by the International Association of Nitrox and Technical Divers (IANTD) is a specialized scuba diving certification program that teaches divers the knowledge and skills necessary to safely and confidently explore caverns and overhead environments in open water.

The course typically consists of classroom sessions, confined water dives, and open water dives, and covers a range of topics including the physics and physiology of diving, equipment considerations, gas management, communication techniques, and dive planning and execution.

During the confined water dives, students learn essential skills such as line handling, reel use, and emergency procedures. These skills are then put into practice during the open water dives, which take place in natural caverns or overhead environments where divers are required to navigate using guidelines and markers.

To enroll in the Cavern Diver course, students must be certified as Advanced Open Water Divers or have an equivalent certification from a recognized scuba diving agency. They must also meet the minimum age requirement (usually 18 years old), have a minimum number of logged dives, and have completed a Nitrox Diver course or equivalent.

Throughout the course, safety is emphasized, and students are trained to manage risks associated with diving in overhead environments. They learn to use the appropriate equipment, follow guidelines and markers, and execute safe and controlled ascents and descents.

Upon successful completion of the course, students will be certified as Cavern Divers and will have the knowledge and skills necessary to safely explore overhead environments within the limits of their training and experience.