Can I do cavern dives with Open Water?

Yes, with a cave-certified guide in the light zone, staying on the permanent line. You need solid buoyancy; the formations are fragile and a silt-out ruins the dive for everyone. Cenote guides will do a buoyancy check first.

How do I get cave certified?

Cavern, then Intro to Cave, then Full Cave, typically over two weeks with an agency like NSS-CDS, GUE, or TDI. Many cave trips bundle the training. Ask for an instructor's schedule when you book.

What does 'rule of thirds' mean?

You turn the dive when you have used one third of your gas, leaving a third to exit and a third for emergencies. It is the foundation of cave gas planning, and your operator will expect you to plan every dive with it.

Cave and Cavern Dive Trips for Overhead Divers

Cavern is daylight, a guideline, and a certified guide within 200 feet of the exit. Cave is the dark beyond it, and only for divers trained to be there. Both are extraordinary. Know which one you have the card for.