A fascinatingly varied reef, half a mile (1 km) long, but only 30 ft (9 m) deep for much of it. The Sac Bajo area, just off the lagoon south of Isla Town, is excellent for snorkeling, and there are spectacular reefs farther from the island (see Isla Mujeres).
This less well-known beach (see Tankah) with just a few hotels is great for relaxed snorkeling and diving away from the crowds. As at Akumal, the reef is quite close to the shore.
Cozumel offers the greatest extent and variety of reef for snorkelers and divers of every level of experience, and visibility is ideal. Paraíso and nearby Chankanaab are “must-sees,” with strangely shaped coral just below the surface.
One of the most vibrant of the mainland beaches and officially protected as a parque marítimo. The reef is unusually close to the shore, so it is great for snorkel tours and introductory diving. The few dive and snorkel operators here offer a personal, friendly service.
The beaches here (see Akumal) provide an important breeding area for sea turtles, which coexist with the development along the bays. The reefs fringing the beaches are wonderful for snorkeling and diving. Akumal is also an important cave-diving center, with Aquatech based at the Villas de Rosa Beach Resort.
Despite busy beaches and the relatively small size of the closest reefs, there’s still lots to see here (see Cancún). “Jungle” snorkeling tours take you through mangroves in Laguna Nichupté and to the reef off Punta Nizuc.
Several high-standard dive operators are based in Playa, taking divers to the reefs nearby and elsewhere along the Riviera.
An extraordinary coral mountain (see Cozumel) with giant canyons that plunge straight from the surface to the depths of the ocean. Nearby, the Yucab and El Cedral reefs are famous for colonies of moray eels and groupers, and tree-like coral heads.
The superb reefs offshore here (see Xpu-Ha) are a favorite destination for Playa del Carmen dive operators. Angelfish, triggerfish, and parrotfish are abundant, along with a luxuriant range of coral.
Delicately veined fronds coming up from the ocean floor and wave graciously in the undersea currents.
Tube-like creatures with a tough, spiny skin that can be seen lying motionless on the seabed or in clefts in the coral.
Among the commonest fish here, yellowtail, blackfin, and other snappers move in huge, gleaming shoals.
Spectacularly colorful fish, with a fan-like shape and luminous stripes and patches in vibrant yellows and electric blue.
Bright, darting little fish, easily recognizable by their black and yellow vertical stripes.
Bizarre fish that, when provoked, inflate themselves by taking in water in order to deter attackers.
These come in many varieties and sizes, but most are very colorful and look as if they are smiling amiably.
Spotted eagle rays, elegantly waving their “wings”, are common around some of the Cozumel reefs.
Many varieties are found around the Yucatán reefs – but attacks on humans are almost unknown.
Now endangered, sea turtles come ashore to lay their eggs on sandy beaches along the southern Riviera.