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Diving Socorro, the ’Mexican Galapagos’

Diving Socorro
The smallest of the islands, Roca Partida

Socorro, a ‘bucket-list’ destination if ever there was one! This group of four Pacific islands some 600km from the coast of Mexico offer unique underwater experiences, as DON SILCOCK found out

Often referred to as the ‘Mexican Galapagos’, the islands referred to as Socorro are so special that in July 2016 they were designated a UNESCO World Heritage Site. Then in November 2017 the Mexican government created what became North America’s largest marine protected area. It made the whole area a national park, declaring total bans on fishing, mining and tourism development and delighting scuba divers.

Socorro is in fact just one of the four islands that make up the Archipiélago de Revillagigedo, the correct name for this location. However, most English-speaking people struggle to pronounce “Revillagigedo”, so with that in mind the pragmatic Mexicans stopped trying to use the formal name among foreigners and now refer to the archipelago simply as Socorro.

Aerial view of san benedicto island and its volcano, archipelago of revillagigedo, mexican pacific.
San Benedicto island

Location, location, location

Semantics out of the way… just what makes these islands so special? The answer is really quite simple – location!

The four islands of San Benedicto, Clarion, Roca Partida and Socorro are actually the peaks of underwater volcanoes that, in turn, are part of a submarine mountain range far below the surface. The overall location is where the north-east Pacific Ocean marine biogeographic region converges with that of the eastern Pacific.

SCUBA diver with a camera swims next to a large Whale Shark on a tropical coral reef
Diver with a whale shark

It is also where the California Current meets the Equatorial Current, all of which creates an incredibly complex and highly productive transition zone.

As the only landfall in such rich waters, the four islands have an incredible mix of resident sharks, manta rays and dolphins. They also act as beacons to migratory species such as humpback whales and whale sharks. Little wonder then that the area is renowned as a big animal paradise.

Whale Shark
Whale shark among the fish

Getting there

The sheer remoteness of the Revillagigedo Archipelago means that diving Socorro is not something to take lightly. Just getting there is an adventure in itself.

For North American divers, it’s not too bad because liveaboard dive boats servicing Socorro operate from Cabo San Lucas, the major resort city on the southern tip of Mexico’s Baja California peninsula. Known for its beaches, sea sports and nightlife, Cabo (as it is commonly referred to) is a busy place that is very well serviced by all the major US airlines.

For the rest of the world long-haul flights are required, and for Australians like me, it’s a journey of epic proportions! Getting to Cabo is just the first part of the trip, however, because it takes another 24 hours by dive boat to reach the nearest Island, San Benedicto.

San Benedicto Island – Volcanic arch to the front and Bárcena to the right
San Benedicto – volcanic arch to the front and Bárcena to the right

San Benedicto

Formerly known as Isla de los Innocentes, San Benedicto covers 10sq km and is the third largest of the islands. Volcanic in origin, it has no source of fresh water and is uninhabited.

Visually striking, the island has two prominent features. Bárcena, near the southern tip, is the volcanic crater left from its eruption in 1952. Viewed from sea level it’s is impressive, but viewed from a drone, it is awesome!

Second are the volcanic arch and nearby pinnacles on the west side of the island, which when viewed up close are spectacular.

The pinnacle at El Boiler
The pinnacle at El Boiler

El Boiler

There are a number of good dive-sites around San Benedicto, including Fondeadero and the Canyon, but none comes close to the incredible El Boiler, which is located near the volcanic arch.

The site consists of a pinnacle that rises from the seabed at 45m, coming to within 10m of the surface. That top area is to be avoided because of surge and swell, but the rest of the site is straightforward, and you select your depth and make your way around the pinnacle.

Curious Oceanic Manta
Oceanic manta ray

El Boiler is a tremendous place to encounter oceanic manta rays, which use the pinnacle as a cleaning station. They are quite accustomed to divers, too, and being intelligent and inquisitive creatures, they will often initiate an encounter and come to you!

Giant Oceanic Manta Ray
Giant oceanic manta

So the best way to dive El Boiler is to stay relatively shallow to conserve air, then make your way around the pinnacle while watching out for the mantas.

Obviously, there is no guarantee they will appear, but they usually do. When that happens, try to separate yourself a bit from other divers and wait. There is no point in trying to chase them, they are too fast, but in any case there is no need to do so – they will come to you.

Incoming Alert
Incoming alert

Silky sharks

While the oceanic manta rays are very much the stars of the show at El Boiler, the dependable co-stars at San Benedicto are the resident population of silky sharks (Carcharhinus falciformis). Clearly very used to the liveaboards that visit the island, the silkies will gather in numbers around the dive-boat looking for scraps.

Relatively large animals, with an intense curiosity and bold attitude, silky sharks are considered to be potentially dangerous. 

Silky shark under the boat at San Benidicto Island
Silky shark under the boat at San Benedicto

Socorro Island

Socorro is by far the largest of the four islands at some 130sq km. It’s an impressive sight when first seen, particularly so from a drone!

It is also the only island that is inhabited – by about 250 Mexican Navy personnel and their families. Their role is to enforce the regulations of the marine protected area and national park.

There are three main dive-sites around the island – Punta Tosca, Roca O’Neal and Cabo Pearce. The first two are interesting dives, but Cabo Pearce is the main attraction and its stars are oceanic manta rays and bottlenose dolphins, as well as the schooling hammerheads often seen out in the blue.

Schooling hammerheads in the blue
Schooling hammerheads keeping their distance

Cabo Pearce, a long “finger” formation on the eastern side of the island, was created by lava flow when Socorro was an active volcano. Under water, that finger extends right out into the deep surrounding waters.

Care is required at Cabo Pearce, because strong currents run either from south to north or vice versa, and they strengthen as they sweep across the top of the underwater part of the lava finger.

Both the mantas and dolphins are used to interacting with divers and will come to you – which makes for some memorable encounters.

Bottlenose dolphins at Cabo Pearce
Bottlenose dolphins at Cabo Pearce

Roca Partida

Located some 100km west of Socorro Island, Roca Partida is the visible tip of a huge underwater mountain. It is hard to imagine a more remote, awe-inspiring and exciting dive-site.

Compared to the other islands Roca Partida is pretty small. Just 100m long and 8m wide, the name means “Split Rock”, which refers to the double peaks – one 25m high and the other 34m.

Its sheer isolation means that Roca Partida has its own ecosystem and resident population of marine creatures. It also attracts migratory animals, and you never know what might appear around the corner.

Swept as it is by strong easterly currents, Roca Partida is best dived by entering the water around the middle of the rock on the east side, which is the “split point” for the current and where the water velocity is minimal. Then it’s a choice of heading left or right to the corners of the rock, where the current is strongest and the action is pumping!

Huge schools of fish pulse in the current, sharks are a constant presence and the chances of random pelagic encounters make the corners of Roca Partida an incredible underwater experience.

Finally, interesting features of Roca Partida are its snoozing whitetip sharks. Located on the eastern side of the rock are several recesses that act as “shark platforms”.

These are where the resident whitetips, which hunt at night, rest by day. Seemingly safe in numbers, the recesses are often crammed to overflowing with sharks.

Sleepy Whitetips
Sleepy whitetips


The four islands of the Archipiélago de Revillagigedo are very special. While only three of the four are dived regularly – Clarion Island is another 290km south-west of Roca Partida and very few dive boats go there – diving Socorro, San Benidicto and Roca Partida is an experience that will stay with you for many years.

The combination of their remote location, exceptional biodiversity, incredible encounters and exciting diving are hard to match – anywhere.

Don Silcock, Scuba Diver’s Senior Travel Editor, is usually based in Bali in Indonesia but is currently hunkered down in Sydney. His website offers extensive location guides, articles and images on some of the best diving locations in the Indo-Pacific region and “big animal” experiences globally.

Photographs by Don Silcock

Also on Divernet: Stopovers On The Highway, Big Time


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