Islas Marietas

The Islas Marietas are a protected UNESCO-recognised national park 35 km offshore, formed by volcanic collapse. The submerged lava tunnels and arches shelter massive schools of fish and a dense reef community. The surface-famous Hidden Beach is above water — the diving equivalent is the swim-throughs and caverns beneath the waterline, home to white-tipped reef sharks resting on sandy floors. Giant manta rays are regular visitors at the cleaning stations on the exposed northern faces.