When I returned to Cancun earlier this year, there was one thing I really wanted to do, and that is diving in a cenote. Cenote is a sinkhole, and a lot of them are connected to underwater caverns via underground rivers. The area that has the most of the cenotes is actually Tulum, but it's not a far drive away from Cancun and a lot of the dive shops will pick you up from Cancun. We decided to drive ourselves so we can visit the Tulum ruins and have dinner in the area. The drive took about two hours. We did our dive with La Calypso and I highly recommend this small dive shop!
If you go to the deeper caves, you have to be an advance certified diver, but there are plenty that you can go with a beginner certification. Our dives that day were in Casa Cenote and Dos Ojos cenote, two very different environments. Casa Cenote has more light, with mangrove roots, while Dos Ojos is more of a dark cavern with tons of stalactites and stalagmites. Yes, under water. It really was like another universe.
Here's a video of what you can see in Casa Cenote. Beautiful light rays, surreal colors, it was really a remarkable place! In this cenote you'll also pass by a spot where fresh water and sea water mixes in.
Diving in Casa Cenote is not too difficult and easier than Dos Ojos because it's more open. Your guide needs to have special equipment and certification for cave diving (with two oxygen tanks), but La Calypso knows what they're doing. The water inside the caverns can be a little bit cool, so a thin wetsuit is recommended.
I think both cenotes were definitely worth seeing and I for one can't wait to do more cenote dives soon!