Another vote for Nachi Cocom. I visited with my 17 yr old son and 11 yr old daughter. No issues ..no problems. http://www.cozumelnachicocom.com/ The place is clean and safe .. and the staff was very accommodating to us. I would recommend the snorkeling trip they offer too .. by far the best I've experienced. No issues getting back to the ship either .. always a cab waiting, or the desk will call one for you. Enjoy!