The Revillagigedo Archipelago

Four volcanic islands and their surrounding waters sit around four hundred kilometres off the Mexican mainland, at a meeting of currents that concentrates large animals to a degree found in very few places. Socorro is the best known, and the archipelago is often called the Mexican Galápagos, though its reputation rests on one thing above all: oceanic manta rays with wingspans over six metres that approach divers repeatedly and appear to enjoy the bubbles. Around them are silky, silvertip and hammerhead sharks, bottlenose dolphins that initiate contact, and humpbacks passing through in winter. UNESCO listed the archipelago in 2016 and Mexico made the whole area a no-take marine park.

What you'll find

• Oceanic mantas - six-metre wingspans, approaching divers deliberately.
• Shark aggregations - silky, silvertip and scalloped hammerhead.
• Roca Partida - a bare rock pinnacle rising from deep water.
• Humpbacks - passing through and audible underwater in winter.

When to go

November to May is the season, with humpbacks from January to March and the warmest water toward the end. The crossing takes over a day each way, so trips are eight to ten days minimum. Boats book a year or more ahead.

Things to know

There is no other way in: liveaboard only, at a cost that puts a trip among the most expensive diving anywhere, and the crossing is long and often rough. Conditions are open ocean with current and surge, so this is advanced diving, not a place to learn. Landing on the islands is generally not permitted. Nothing about the wildlife is guaranteed.

Nearby

Cabo San Lucas is the departure port; Cabo Pulmo is on the other side of the peninsula.