A visit to Akumal is a snorkeling experience, you can walk right in the beach and see remainings of a ship wreck and most probably will be able to find sea turtles and rays that will allow you to take some great pictures, Akumal  is a highly protected area, you should plan on swimming with your t shirt on or staking up on bio degradable suntan lotion to protect the beautiful creatures that attracted you there on the first place. Akumal dive Shop has fins and snorkel gear for rent, and you can use it at the beach and then at the Yalku lagoon nearby, where snorkeling is beautiful, and not as crowded as some of the parks in high season.