I believe “permission” (& payment of fees) may be required to visit the Alacranes Reef & Islands.
The Alacranes reef, is an emergent platform reef that forms part of the Campeche Bank, itself an underwater extension of the
Yucatan Peninsula, i
s the only coral reef in Yucatan, and was declared a national reserve (Marine Protection Area) in 1994.
It is a large reef system shaped as a half moon with 5 islands (Isla Desterrada, Isla Blanca, Isla del Muerto, Isla Pérez and Isla de los Pájaros) and an arcing reef of about 16 miles in length on the east side, by about 6 to 8 miles wide.
The
reefs are spectacular, and many say that they are better than Cozumel. Visibility is usually 100 feet or more. The
water depths are about 160 feet deep off the south end and about 210 feet off of the north end of Alacranes.
Isla Pérez (about 78 nautical miles off the Yucatan coast @ 22̊ 23' 40 N x 89̊ 42' 0 W), is at the southern end of Alacranes reef, and has a lighthouse located on it maintained by a semipermenant population.