Dive Site: Chatham Bay

About Chatham Bay

Chatham Bay serves as a pivotal and popular dive site at Cocos Island, strategically positioned on the northeast side of the bay, off Manuelita Island. This site is frequently utilized for check-out dives, allowing divers to fine-tune their equipment in a relatively sheltered environment before venturing to more exposed locations. Despite its ease of access, Chatham Bay is far from mundane, boasting a rich ecosystem that appeals to a wide range of divers. The topography consists primarily of a sandy bottom, generously dotted with hard coral formations. These corals provide crucial habitats for an impressive variety of marine species, making the site an excellent location for macro photography and observing smaller reef inhabitants. Depths are generally shallow, contributing to its designation as an easier dive, suitable for divers of varying experience levels. While Cocos Island is renowned for its pelagic encounters, Chatham Bay highlights the island's diverse marine life beyond just large sharks. Divers can expect to find a vibrant community of colorful reef fish, numerous giant hermit crabs, various urchins, and several species of lobsters and eels. Occasional sightings of white-tip sharks, hammerheads, and other larger marine animals at nearby cleaning stations add to the excitement. The dive experience here is typically relaxed due to protection from strong currents and waves, allowing for extended bottom time and detailed exploration. Entry and exit are straightforward, often conducted via tenders from liveaboards, ensuring comfort and convenience for all participants. This site often marks the beginning of a Cocos Island diving itinerary, offering a gentle introduction to the region's underwater wonders.

Dive site facts: Chatham Bay

Depth

5–30 m

Typical dive

15–20 m, 50–60 min

Current

Mild to moderate

Visibility

15–30 m

Water temperature

22–27 °C

Entry

Tender

Level

Open Water Diver

Dive type

Reef, Macro, Cleaning station

Night dive

Not permitted

Region / port

Cocos Island

Coordinates

5.55, -87.03

Conditions & Currents

Chatham Bay is notably sheltered from strong surface conditions, making it a reliable alternative when other sites experience challenging currents. While typically an easy dive, the surrounding Cocos Island environment can feature significant open-ocean currents, wave action, and surge, especially during summer monsoon-like rains. Descents and ascents at more exposed sites are often conducted in open water with current, requiring proficiency in buoyancy control and surface marker buoy deployment. Visibility can fluctuate from 15 to 30 meters, influenced by plankton levels, which in turn attract large pelagics. Thermoclines are common, with water temperatures ranging from 22 to 27 degrees Celsius, necessitating appropriate wetsuit thickness.

Marine life & sighting chances

Whitetip reef shark

common

Scalloped hammerhead shark

May–November · occasional

Tiger shark

occasional

Frogfish

common

Giant hermit crab

common

Lobster

common

Moray eel

common

Snapper

common

Parrotfish

common

Butterflyfish

common

Marble ray

occasional

Octopus

occasional

Dive profile & how the dive runs

Dives at Chatham Bay typically begin with a tender drop-off directly onto the site, usually for a checkout dive. You will descend onto a sandy bottom that gradually slopes, dotted with various hard coral formations. The route often involves a leisurely exploration of these coral patches, searching for smaller reef life and macro subjects. Divers maintain depths generally between 10 to 20 meters, allowing for ample bottom time to observe the rich biodiversity. You can expect to drift gently along the protected bay, following the contour of the reef. The turn point is usually signaled by the guide, leading back towards the tender for ascent. The safety stop is conducted in the shallow, calm waters of the bay, providing a comfortable and relaxed conclusion to the dive.

Underwater photography

Chatham Bay is an ideal location for macro photography, so a lens like a 60mm or 100mm/105mm is highly recommended to capture the intricate details of frogfish, giant hermit crabs, and various eels. For wider scenes, such as schools of reef fish or occasional shark sightings, a wide-angle lens can be effective, especially given the typically good visibility within the bay. External strobes are beneficial for illuminating subjects and restoring natural colors, particularly for macro shots in deeper sections or under ledges. Maintaining excellent buoyancy is crucial to avoid disturbing the sandy bottom and delicate coral, which is vital for clear shots and ethical interaction. Patience is key; allow marine life to acclimate to your presence before attempting close-up shots.

Combine with nearby dive sites

• Manuelita Coral Garden

  A nearby site protected from currents and waves, known for reef fish and whitetip reef sharks.

• Ulloa and Lobster Rock

  Close to Chatham, popular for schools of reef fish and whitetip sharks receiving cleaning services.

• Manuelita Outside

  Offers a variety of marine life, including eagle rays, Galapagos sharks, and schooling jacks.

• Bajo Alcyone

  A submerged mountain renowned for schooling hammerheads and pelagic encounters.

• Dirty Rock

  A large island site known for schools of marble rays and hammerheads.

Getting there & logistics

Access to Cocos Island, including Chatham Bay, is exclusively via liveaboard, typically departing from Puntarenas, Costa Rica. The journey to Cocos Island takes approximately 32-36 hours across open seas. Most liveaboard itineraries are 8 to 10 nights, offering multiple days of diving around the island. The nearest international airport for arrivals is Juan Santamaría International Airport (SJO) in San José, with transfers arranged to Puntarenas. Divers should plan for at least one night in San José before and after the liveaboard trip to account for travel and potential delays. All diving activities, including those at Chatham Bay, are conducted from tenders. A Cocos Island National Park fee is usually included in the liveaboard package.

Safety & environment

Cocos Island is remote, and the nearest recompression chamber is in San José, Costa Rica, necessitating a significant evacuation time by air. Therefore, comprehensive dive accident insurance, such as DAN, is mandatory for all divers. Site-specific hazards at Chatham Bay are minimal due to its sheltered nature, but general Cocos Island diving requires advanced skills, including excellent buoyancy control and comfort with open-ocean descents/ascents in currents. Always follow your dive guide's instructions, especially regarding proximity to marine life and maintaining group cohesion. Night dives are not permitted at Cocos Island, and divers are advised to respect the protected status of the marine park.

Who it suits — and who it doesn't

FAQ

Chatham Bay FAQ

Liveaboards diving Chatham Bay

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

Cocos Aggressor

Costa Rica

22 guests37.8 m

$636/day

Sea Hunter

Costa Rica

20 guests

$690/day

Okeanos Aggressor II

Costa Rica

24 guests36.6 m

$504/day