Destinations  /  The eastern Pacific  /  Cocos Island
Destination

Cocos Island

Costa Rica

Liveaboard only, 550 km offshore. Hammerhead schools at fixed cleaning stations, and the white-tip reef shark night dive.

Season
Year-round; Jun–Nov strongest currents
Water
24–28 °C
Visibility
10–30 m
Typical depth
10–40 m
Species recorded
51 of 1316
Sites
13 named
DE-01
cocos island · offshore pinnacle · blue water · sharks · wide
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What the diving is like

A single uninhabited island 550 km off the Pacific coast of Costa Rica, reachable only by liveaboard, and dived almost entirely for large animals. The diving is done on submerged pinnacles and seamounts around the island and on the walls of the island itself. Hammerhead schools come to fixed cleaning stations, where barberfish and king angelfish work over them; this is the most reliable hammerhead diving anywhere, and it is reliable because the stations are fixed rather than because the sharks are unusually abundant. The white-tip reef shark night dive is the other reason people come. After dark the sharks hunt across the shallow reef in loose packs of dozens, and the behaviour is easier to watch here than anywhere else. Alongside those: silvertip, Galapagos, silky and occasionally tiger sharks, marbled rays on the sand, mobula and giant manta at the seamounts, and dense stationary schools of bigeye trevally and creolefish. Macro is thin by comparison, but the rosy-lipped batfish is endemic and the Pacific seahorse occurs on the deeper gorgonians. Water is 24–28 °C with a thermocline that can drop into the low twenties at the deeper seamounts. Current is constant and often strong; reef hooks are standard.

The shape of a day

Three to four dives a day from tenders, plus a night dive. Crossings between the island's dive areas are short. Most of the day is on the boat, since landings on the island are restricted and there is nothing ashore. Trips run seven to ten diving days. The island is a national park and a UNESCO World Heritage site; a ranger visit and a park briefing are part of the itinerary.

Getting there

Fly to San José (SJO), then transfer by road to Puntarenas, where the boats leave. The crossing takes 30 to 36 hours in each direction, so a ten-night trip gives roughly seven diving days. The crossing can be rough. Anyone prone to seasickness should plan for it rather than hope.

When to come

Diveable year-round, with two useful patterns. The rainy season, roughly June to November, brings rougher crossings, more rain and reduced visibility, but the strongest currents and the largest hammerhead aggregations. The drier season, roughly December to May, gives calmer crossings and better visibility, with whale sharks and mantas more frequently reported. Neither season is wrong. The trade is comfort against animal density, and most divers who have done both go back in the rainy season.

Fees and what is not included

Liveaboard only, and priced accordingly: there is no budget route to Cocos. Park fees are charged per diving day and are usually separate from the berth. Nitrox and gear rental are typically extra. The currency is the Costa Rican colon, but trips are almost always quoted and settled in US dollars.

Named sites

13 sites, described by ground and depth. What is found on each one is not published — naming the exact spot a rare animal sits on is how it gets crowded and moved on. The species recorded at this destination are listed below, and the reasoning is set out in the editorial policy.

  1. Bajo Alcyone (Alcyone Seamount)

    Offshore, about 1.5 km southeast of the island · Boat · Rock · 25–36 m

    A detached volcanic seamount rising from deep water to a flat rock plateau at about 25 metres. The plateau is cut by channels and crevices, and steep rock sides fall away below it on every side.

    Current is strong and often surging. The descent is made down a fixed mooring line, and a marked thermocline with a sharp temperature drop is usual below about 30 metres.

  2. Dirty Rock (Roca Sucia)

    Off the northwest coast · Boat · Rock · 15–35 m

    A group of jagged volcanic pinnacles and boulders that break the surface, with a second submerged pinnacle topping out near 18 metres about 100 metres away. Steep rock walls and boulder slopes drop from the pinnacles to sand and broken rock at around 35 metres.

    Current can be very strong and surge is felt around the shallower rocks, so divers commonly hold onto the rock to keep position.

  3. Manuelita Outside (Manuelita Deep)

    Manuelita Island, ocean-facing north and west side · Boat · Rock · 18–35 m

    The exposed outer side of a 490 metre long rock islet, where a slope of very large boulders runs down from about 18 metres onto sand. The northern end steepens into a near-vertical rock wall that continues past 40 metres.

    Current is variable and often strong, the water at the extreme northern tip is confused and turbulent, and surge is noticeable among the shallower boulders.

  4. Manuelita Channel (Manuelita Garden, Manuelita Inside)

    Manuelita Island, sheltered inner side and the channel · Boat · Mixed · 6–27 m

    The protected inner face of the islet is a shallow hard-bottom shelf and sand slope running from about 6 metres to an outer edge near 21 metres. The channel between the islet and the main island has a floor of scattered large boulders and sand at about 27 metres.

    The inner side is sheltered from swell and is the usual site for night dives. The channel itself can run a strong tidal current and is normally dived as a drift towards Chatham Bay.

  5. Punta Maria (Maria Point)

    About 500 metres off the west coast · Boat · Rock · 24–36 m

    A large seamount whose broad flat crown lies at roughly 24 to 25 metres, with two smaller rock pinnacles to the north topping out near 20 metres. Steep sloping rock walls and a sand channel fall away from the crown to below 36 metres.

    Current frequently sweeps hard across the whole site, there is no shallow rock on which to make a safety stop, and a surface marker buoy is needed for the ascent.

  6. Big Dos Amigos (Dos Amigos Grande)

    Dos Amigos islets, off the southwest · Boat · Rock · 18–36 m

    The larger of two steep volcanic islets, carrying a large rock arch in its southwest corner that spans from about 21 metres at the top of the opening down to a sand floor near 33 metres. Boulder slopes run deeper on either side of the arch.

    The direction of the dive is set by the current on the day, and swell breaking against the islet makes the shallow rock surgy at the start of the descent.

  7. Small Dos Amigos (Dos Amigos Pequena)

    Dos Amigos islets, off the southwest · Boat · Rock · 18–36 m

    A conical volcanic islet with bare rock slopes above and below the waterline. The rock steps down in boulders and short ledges from about 18 metres to sand and broken rock below 36 metres.

    This is the first point the open-ocean current meets the island, surge on the west face is heavy, and the site is often unusable in the wet season.

  8. Submerged Rock

    Off the southeast, close to Bajo Alcyone · Boat · Rock · 12–33 m

    A small seamount whose flat top sits just below the surface, with steep sides broken by cracks and crevices. A large tunnel runs right through the rock, its upper opening at about 21 metres and its lower exit at about 25 metres.

    Current is mild to moderate and the dive is normally run as a drift along the shallower slope, though swell pushes back and forth inside the tunnel.

  9. Viking Rock

    Northwest corner of Wafer Bay · Boat · Wall · 15–35 m

    A small helmet-shaped rock islet whose vertical wall drops from the surface to about 15 metres. Below that the rock steps away in a series of small plateaus and short walls, like terraces, down to around 35 metres.

    Currents are usually mild and tidal and may set the direction of the dive. The stepped profile suits a multi-level ascent.

  10. Lobster Rock (Roca Langosta)

    Off the northeast coast, near Chatham Bay · Boat · Mixed · 12–33 m

    A narrow finger of rock, heavily cut with cracks and fissures, standing alone on a flat white sand bottom. The rock rises from sand at about 33 metres to a top near 12 metres.

    Conditions are usually calm with little current or surge and water of about 26 to 29 degrees Celsius. Often combined with the neighbouring Ulloa as one drift.

  11. Silverado

    Off the east coast, south of Chatham Bay · Boat · Mixed · 5–15 m

    A low submerged rock standing roughly two metres proud of the bottom, with its top about five metres below the surface. A gradual sand slope runs away from its base to around 15 metres.

    Shallow and generally sheltered with only light current, which makes it one of the easier sites at the island. Sources place it in three different quarters of the island; the east and southeast reading is the one two independent sources agree on.

  12. Chatham Bay (Bahia Chatham)

    Northeast coast · Boat · Mixed · 5–18 m

    A shallow sand bottom inside the main anchorage bay, with scattered patches of hard reef and small rock outcrops. The sand slopes gently away from the shore to about 18 metres.

    Sheltered with little current and normally used as the first orientation dive of a trip. The ranger station in the bay administers the national park permit that every dive at the island requires.

  13. Ulloa

    Off the northeast side, near Chatham Bay · Boat · Rock · 10–20 m

    A shallow rock shelf and boulder ground running out from the shoreline rock on the northeast side, sloping gradually away into sand.

    Normally dived as an easy drift in mild current and often run as one dive with the neighbouring Lobster Rock.

Site names are as the operators and guides here use them. Descriptions are drafted and need correcting by someone who dives them. Tell us what is wrong and it will be corrected.

Recorded here

51 of the 1316 species in the index have a confirmed record at Cocos Island, ordered by how hard each is to find here.

Salp
Salpida
Open water · 0–30 m
3 stars of 5, a good week should turn one up

The other 50, recorded here but not yet photographed

Every one has a page and a record at Cocos Island. They are listed rather than shown because nothing has been photographed or logged for them yet.

Also in The eastern Pacific

Cold upwelling on the equator, and a fauna cut off from the Indo-Pacific by five thousand kilometres of open ocean, so almost nothing here is on the other lists. Current-driven, often cold, frequently not clear, and dived for large animals rather than for coral.

Galapagos Islands Ecuador Cold upwelling on the equator. Hammerhead schools at the northern islands, sea lions and the red-lipped batfish in the south. Current-driven and demanding. Islas Revillagigedo Mexico Four volcanic islands 400 km out in the open Pacific, dived from liveaboards out of Los Cabos. Bare rock, seamounts and vertical walls, with almost no coral reef.