Casa Cenote is located just outside of Tulum, in an "almost" town called Tankah. There is a small entrance fee (20 pesos) and kayaks are available for rent for 100 pesos an hour. The cenote is extremely close to the ocean, just a few steps across the road brings you to the incredible Caribbean Sea and a small beach side restaurant.
The snorkeling was great fun, lots to see under the cool waters of Casa Cenote. I think instead of blah blah blahing about it, I'll just let the pictures and video speak for themselves.
And there you have it, a glimpse of Casa Cenote, another great day trip out of Cancun.