Arrecifes de Cozumel National Park, Marine national park in Quintana Roo, Mexico

Arrecifes de Cozumel is a protected marine area off the coast of Cozumel Island in the Mexican state of Quintana Roo. The water territory runs along the southern side of the island and includes coral formations, steep underwater walls and shallow lagoons near the shore.

The area was officially designated a national park in July 1996 to protect the coral reefs from increasing tourist use. This measure followed years of efforts by biologists and local groups who had documented the decline of underwater habitats.

The park's reefs lie within the Mesoamerican Barrier Reef System, the second largest coral reef system in the world, and the island sits about 20 km off the Yucatán Peninsula. The splendid toadfish (Sanopus splendidus), listed as vulnerable by the IUCN, lives only on the reefs around Cozumel. Black coral, once a hallmark of the deeper reefs, declined from the 1960s to the mid-1990s through overharvesting and had not recovered by 2016.

Visitors can enter the marine area only with registered operators who must follow set routes and protection guidelines. Dives and snorkeling trips usually take place in the morning when the water is calmest and visibility remains best.

Some coral walls drop over 100 feet (30 meters) vertically and form natural tunnels through which divers can swim. In these deeper areas, sponges grow in bright colors that do not appear in shallow water.