South of Cancun on the eastern tip of the Yucatan, the snorkeling at Xel-Ha offers exceptionally clear water due to freshwater currents. Xel-Ha Park is known as a natural aquarium with over 90 species of marine life. During an Xel-Ha snorkeling trip, you're likely to see parrotfish, snapper, wrasse, sergeant majors, grouper, surgeons, angelfish, pufferfish, damsels and barracuda. The water depth ranges from 5 to 15 feet deep, and this dive site has low visibility typically under 20 feet. Keep in mind that there is no coral growth since there is plenty of incoming fresh water. The Xel-Ha locals refer to snorkeling as esnórquel.
To reach the snorkeling in Xel-Ha by air, you will need to fly into Cancun International Airport (Aeropuerto de Cancun - CUN). Some of the hotels provide shuttle vans or there are shuttle vans to be hired down to Xel-Ha. Renting a car to drive around can be hazardous do to the potential for unwarranted police stops resulting in required immediate cash payments. An alternative airport option is to fly into Aeropuerto Internacional de Cozumel (CZM) and take the ferry from Cozumel to Playa del Carmen. From there, you can take a much shorter shuttle van down to Xel-Ha.
Note: while snorkeling offshore here, keep in mind that from November through March you might encounter bull sharks right off the beach.
Overall, Xel-Ha is the 9th most popular snorkel dive spot of all 40 snorkeling dives in Mexico.