Commonly referred to as the Tortugranja (Carr. Sac Bajo 5, tel. 998/888-0507, 9 a.m.–5 p.m. daily, US$2.50), this modest sea turtle sanctuary on Isla Mujeres' southwestern shore makes for an interesting stop on your golf-cart tour of Isla Mujeres.

The one-room cement structure contains several enclosures with sea turtles of different ages and species. The tank of just-hatched tortuguitas is always a hit; please respect the rules (and huge signs) and refrain from touching or picking them up. During the nesting season (June–August), one section of sand is fenced off, and eggs collected from nests are transplanted here for protection.

Small aquariums along the walls contain sea anemones, sea horses, and the deadly rockfish, among others.

Between June and August, travelers may be able to accompany the center’s workers to look for fresh sea turtle nests on the island’s eastern shore and relocate eggs to protected areas, and, until October and November, help release hatchlings into the sea.

Both activities take place in the evening several nights a week, but are not formal tours. Those interested should inquire at the center, and having basic Spanish (and possibly your own vehicle) will make participating much easier. There’s no charge, but a tip is customary.