Dive Site: Ulloa

About Ulloa

Ulloa and the closely situated Lobster Rock together form a dynamic dive site located off Cocos Island, a remote UNESCO World Heritage Site in Costa Rica's eastern Pacific. Divers can seamlessly transition between these two distinct areas, starting at one and finishing at the other, exploring a rich volcanic topography at depths between 15 and 30 meters. The site is characterized by schools of reef fish, cottonmouth jacks, and surgeonfish, creating a vibrant underwater spectacle. A unique plateau covered with Rhodolith, a red algae resembling coral, lies just north of Lobster Rock, providing a habitat for the endemic Cocos rosy-lipped batfish, flounders, and various eels. While typically sheltered from strong surface conditions, currents can occasionally be swift, leading to drift on ascent. This variability makes it a reliable alternative when other, more exposed Cocos sites like Alcyone become too challenging. Visibility at Cocos Island generally ranges from 15 to 30 meters, with water temperatures between 22 and 27 degrees Celsius, often featuring thermoclines. Ulloa is particularly noted for abundant whitetip reef sharks, which frequent cleaning stations attended by gobies. Occasionally, larger pelagics such as tiger sharks, manta rays, and smaller silvertip sharks make appearances, adding to the site's allure for experienced divers arriving via liveaboard from Puntarenas.

Dive site facts: Ulloa

Depth

15–30 m

Current

Mild to swift

Visibility

15–30 m

Water temperature

22–27 °C

Entry

Tender

Level

Advanced

Dive type

Reef, big_animals, cleaning station

Night dive

Not permitted

Region / port

Cocos Island, Costa Rica

Coordinates

7.9274° N, 86.1572° W

Conditions & Currents

While Ulloa and Lobster Rock are generally sheltered from strong surface conditions, currents can still be swift at times, potentially causing divers to drift during ascent. The site serves as a good alternative when more exposed Cocos locations experience challenging currents. Visibility throughout Cocos Island dive sites, including Ulloa, ranges from 15 to 30 meters, influenced by plankton levels that attract pelagics. Thermoclines are common, leading to water temperature fluctuations between 22 and 27 degrees Celsius, necessitating appropriate wetsuit thickness. Divers should be proficient in buoyancy control and comfortable with potential drift, as all dives are conducted via tenders from liveaboards.

Marine life & sighting chances

Whitetip reef shark

common

Cocos rosy-lipped batfish

occasional

Cottonmouth jack

common

Surgeonfish

common

Black triggerfish

common

Convict tang

common

Flounder

occasional

Snake eel

occasional

Garden eel

occasional

Ray

occasional

Tiger shark

occasional

Manta ray

occasional

Silvertip shark

occasional

Dive profile & how the dive runs

Diving at Ulloa and Lobster Rock often begins with a tender drop-off allowing divers to explore both sites sequentially. You might start at one end, such as Ulloa, and finish at Lobster Rock, or vice versa. Depths typically range from 15 to 30 meters, allowing for exploration of the volcanic pinnacles and the Rhodolith-covered plateau located north of Lobster Rock. The dive will involve observing schooling reef fish and the numerous whitetip shark cleaning stations. In the afternoons, you might witness black triggerfish and convict tangs spawning at the base of Lobster Rock. Due to potential swift currents, particularly during ascent, maintaining good buoyancy is important. The dive concludes with a safety stop, often in the calmer areas, before returning to the liveaboard's tender.

Underwater photography

Ulloa and Lobster Rock offer diverse photographic opportunities. For the vibrant schools of reef fish, jacks, and spawning triggerfish, a wide-angle lens is ideal. Consider using strobes to bring out the true colors of the abundant marine life and the unique Rhodolith formations. For the elusive Cocos rosy-lipped batfish, eels, and other macro subjects found in the sandy flats, a macro lens (60mm or 100mm/105mm) will be beneficial. Be prepared for varying visibility due to plankton, and practice good buoyancy control to avoid disturbing the sandy bottom or coral-like algae, especially when photographing delicate subjects. When pelagics like manta rays or sharks pass by, be ready to switch to or use a versatile zoom lens.

Combine with nearby dive sites

• Lobster Rock

  Adjacent to Ulloa, often dived together.

• Chatham Bay

  Sheltered site off Manuelita Island, good for checkout dives and macro.

• Manuelita

  Features multiple channels and cleaning stations with various pelagics.

• Dirty Rock

  Known as a primary cleaning station for large hammerhead schools.

• Pajara Island

  Pajara Island, located off Cocos Island, is known for its tranquil diving conditions and thriving marine ecosystem.

Getting there & logistics

Access to Cocos Island, and thus Ulloa, is exclusively via liveaboard vessels departing from Puntarenas, Costa Rica. The crossing to the island takes approximately 32-36 hours. Typical itineraries range from 10 to 12 nights, providing 5 to 6 full days of diving. Dive operations are conducted using tenders, launching from the liveaboard. A permit is required to visit the UNESCO World Heritage site and national park, and there are no shore excursions without a ranger. There are no airports on the island, and the nearest major international airport is Juan Santamaría International Airport (SJO) in San José, requiring a ground transfer to Puntarenas. Divers should plan to stay a night on the mainland before and after the liveaboard trip due to travel times.

Safety & environment

Diving at Ulloa requires an advanced level of experience due to strong currents that can occur, especially during ascent, and the remote nature of Cocos Island. The nearest recompression chamber is located back on the Costa Rican mainland, implying significant evacuation time in case of a dive emergency. Comprehensive dive insurance, including coverage for emergency evacuation and recompression treatment, is therefore mandatory. Divers should be proficient in buoyancy control, capable of managing currents, and comfortable with open-water descents and ascents from tenders. Night dives are not permitted. Always follow the instructions of your dive guides, as the dive team’s priority is diver safety in this remote environment.

Who it suits — and who it doesn't

FAQ

Ulloa FAQ

Liveaboards diving Ulloa

These liveaboards may visit Ulloa on selected itineraries — the exact dive sites depend on departure, weather and conditions.

Cocos Aggressor

Costa Rica

22 guests37.8 m

$477/day

Sea Hunter

Costa Rica

20 guests

$690/day

Okeanos Aggressor II

Costa Rica

24 guests36.6 m

$582/day