I would also highly recommend eagle ray divers. We used them last year for a snorkel trip and they were awesome. My Mom, sis and I were the only ones on the boat. we actually had a guide go with us into the water and snorkel with us. He (carefully) brought things up from the bottom for us to see and touch, pointed out fish and even a couple barracudas, best of all kept a close watch on our Mom (poor swimmer) so my sis and I were able to relax and enjoy the "view." The boat followed along with us the whole way and was right there when it was time to get out. Another benefit was that we wanted to be able to swim with the dolphins as well as do the snorkel trip. They specially set up our trip so we would have time to do both! I am going back to Cozumel with friends in August and am already planning my eagle ray excursion! I'm thinking intro to scuba this time.