El Cien

El Cien is a remote offshore coral reef at the southern tip of Cabo Pulmo National Park, characterized by hard coral formations and rocky ledges that slope to about 21 m. The reef supports very large schools of reef fish, with dense aggregations of groupers and snappers noted as a main attraction. Access is by boat only to the exposed reef edge; the dive follows an open reef slope with no overhead ceilings, and divers descend along coral and sand to roughly 21 m and can roam freely over the reef. Visibility is generally good in calm seasons (often 15-30 m) but can drop below 10 m in winter during plankton blooms and poorer weather. Water temperatures range from about 15 °C in winter to 29-30 °C in summer. Moderate currents may be encountered due to the open-ocean location; standard considerations for deeper reef dives apply (manage bottom time and safety stops). Marine park regulations apply, including use of mooring buoys, no fishing, and group-size limits.