North of Cancun, the snorkeling at Isla Contoy is known for turtle encounters. Within the Contoy Island National Park, the island of Contoy does not have any tourist services or lodging. It is located about 30km north of Isla Mujeres. Isla Contoy is accessible by private boat tours from Puerto Juarez or Isla Mujeres, and the tours are limited to a total 200 visitors per day to the island. There is a main pier that accesses the national park visitor center and museum. During Isla Contoy snorkeling, you may encounter loggerhead turtles, green sea turtles, hawksbill turtles and leatherback turtles along with whale sharks off-shore.
Offshore, there are several popular snorkeling dive destinations. Off the north end, the Las Calderas snorkeling dive site is a strip reef along with an old wreck to check out. The reef consists of elkhorn coral and large brain coral formations among the sand flats with turtle grass. The dive site is known for some surge and currents. For this boat-accessed snorkeling site, the water depth is about 20 feet deep.
Off the southeast end, the Ixlache Reef is the most popular snorkeling dive site. For this boat-accessed snorkeling site, the water depth ranges from 10 to 20 feet deep. The currents and surges are pretty consistent at Ixlache Reef, and therefore the visibility is usually not as good as other places ranging around 20 to 30 feet. Keep in mind that Hurricane Roxanne in 1995 had smothered the reef with sand and it has been recovering since with new coral growth.
To reach the snorkeling at Isla Contoy, you will need to contact one of dive tour charter boat companies to arrange a trip out here.
Overall, Isla Contoy is the 28th most popular snorkel dive spot of all 40 snorkeling dives in Mexico.