What the diving is like
The four islands are the tops of volcanoes rising from deep ocean floor, and they sit far offshore with nothing shallow between them and the open Pacific. Socorro is the largest at about 132 square kilometres and rises to 1,130 metres at Cerro Evermann; it last erupted in 1993. San Benedicto is much smaller at about 6 square kilometres and carries the Barcena cone, which formed in an eruption in 1952, so parts of that island are geologically very recent. Clarion, the westernmost, is about 20 square kilometres and rises to 335 metres. Roca Partida is not an island in any practical sense but a bare rock roughly 34 metres high and a few tens of metres across, the visible tip of a submerged mountain. What you dive is rock. The ground is volcanic: lava flows that continue below the waterline as long fingers and ridges, boulder fields, terraced ledges, steep slopes and, at Roca Partida, an almost vertical wall dropping into water hundreds of metres deep. There is effectively no coral reef in the archipelago. Encrusting growth on the rock is low, and the colour comes from the rock itself rather than from hard coral structure. Sand, where it exists, is dark volcanic grit in pockets between boulders, and it is a small part of the seascape. Current is a constant factor. Operators report up to about two knots at the more exposed sites, and it is strongest at the ends and corners of the rocks, at the tips of the lava fingers such as Cabo Pearce, and around Roca Partida. The usual technique is not to hook in but to work along the rock and shelter in back eddies behind boulders and ridges. Reef hooks are not generally used, and dive knives and torches are not permitted in the park. Fast entries, often negative entries or immediate backward rolls from the skiffs, are normal at sites like El Boiler where you have to reach the rock before the current takes you past it. Surge is the second factor. Several sites have shallow summits, and swell breaking over them produces strong back-and-forth water movement in the top ten metres. El Boiler takes its name from that effect. The exposed sides of Socorro, Punta Tosca and Punta Norte, are dropped from the schedule when the swell is running. Thermoclines are usual, commonly between 20 and 30 metres, and they deepen and sharpen in February and March, so the bottom of a dive can be several degrees colder than the surface. The islands differ from each other. San Benedicto has the shallow-summited offshore pinnacle at El Boiler, the horseshoe rock and drop-off at El Canyon on the south end, and two lee-side sites, El Fondeadero and Las Cuevas, that are calmer and shallower. Socorro has the longest and most varied shoreline, with lava-finger headlands at Cabo Pearce and Punta Tosca, a detached rock with a shallow plateau at Roca O'Neal, and a sheltered shallow bay used as a check dive. Roca Partida is the extreme case: no shelter, no shallow ground, wall diving in blue water on all four aspects, with ledges cut into the faces. Clarion is a separate proposition, about 200 kilometres beyond Roca Partida, and is very rarely visited.
The shape of a day
Liveaboard only. There is no land-based diving, no shore access without a permit, and no accommodation for visitors. Boats normally run three to four dives a day from small skiffs launched from the mother vessel, dropping divers on the site and picking them up in open water afterwards. Night diving is not permitted anywhere in the park, so the diving day ends in the late afternoon. Passages between islands are made overnight where possible: San Benedicto to Socorro is a short crossing of about 48 kilometres, but Roca Partida lies far to the west, and the leg out to it and back costs most of a night and a day, which is why itineraries usually reach it on only one or two days. Part of one day is given over to the compulsory check-in at the naval station on Socorro. Operators set experience requirements because of the current, the depth and the open-water pickups. Most ask for an advanced certificate and many state a minimum of 50 logged dives, some 50 to 100. Nitrox is strongly recommended and some operators effectively require it. What matters more than the paperwork is reliable buoyancy control, being comfortable entering and leaving a small skiff in swell, and being able to work in current without holding onto the rock. Decompression diving is not allowed and the park limit for recreational diving is 35 metres.
Getting there
All trips leave from Baja California Sur, either from Cabo San Lucas or from the marina at San Jose del Cabo, both served by Los Cabos International Airport (SJD). The archipelago lies roughly 400 to 460 kilometres south-southwest of Cabo San Lucas. The crossing to San Benedicto, the first island reached, is given as 24 to 30 hours each way, and one source states that 30 to 36 hours is more realistic in poor weather. Trips are typically 8 to 10 days in total, which gives five to seven days of diving once the two crossings are deducted. Longer itineraries are run when Roca Partida or Clarion are included.
When to come
The season runs from November to June, and a few operators continue to mid-July. Boats do not run from about mid-summer to October because of the storm and hurricane risk. November and December give the warmest water of the season, around 24 to 27 degrees, with moderate currents and generally settled conditions. January to March is the coldest part, around 21 to 24 degrees, with stronger currents and sharper thermoclines, but often good visibility. April to June brings warming water and more plankton, which can reduce visibility. If comfort and calm water matter most, come at the start of the season; the middle of the season is colder and has stronger current.
Fees and what is not included
The main charge on top of the trip price is the national park fee for Parque Nacional Revillagigedo, set by CONANP and collected by the liveaboard operator. It is charged per diver for each day of diving, not per trip. It was roughly doubled with effect from 1 January 2025, and published figures for that year range from about 3,266 to 3,760 Mexican pesos per diving day, which was in the region of 190 US dollars a day at the rates operators were using. On a six-day diving itinerary that is somewhere above 1,100 US dollars per diver. Sources do not agree on the exact figure and some state that Mexican value added tax at 16 per cent is charged on top. Reductions are available on production of documents in advance, reportedly for people aged 60 and over, for students and teachers, and for Mexican nationals and residents, but the terms differ between sources. Operators also commonly charge a port fee of around 65 US dollars per person in cash on board and a nitrox supplement of around 140 US dollars for the trip, and Baja California Sur levies a tourism tax of 470 pesos per international visitor. Crew gratuities are customary and not included. These amounts are set in pesos and change by government decree, so confirm the current figure with the operator before booking.