Bajo Alcyone

Bajo Alcyone: The Hammerhead Capital of Cocos Island

Prepare for an unparalleled pelagic encounter at Bajo Alcyone, a legendary dive site off Cocos Island’s eastern flank. First charted by the Cousteau Society research vessel Alcyone, this exposed seamount is globally renowned as one of the top dive sites on Earth, offering arguably the planet’s most reliable schooling-hammerhead encounters.

Diving Conditions and Site Characteristics

• Dive Site Type: Bajo Alcyone is a dramatic seamount, a submerged pinnacle rising from approximately 50 meters to a summit at 18 meters. This makes it a prime location for drift diving.
• Depth: Divers will typically explore depths ranging from 18 m to over 40 m, with much of the action at the cleaning stations occurring between 25 m and 35 m.
• Current: Expect strong to very strong currents at Bajo Alcyone. We often utilize a fixed line for descent and ascent, and divers may use reef hooks to maintain position and observe the incredible marine life.
• Water Temperature: The water temperature generally ranges from 22°C to 28°C. However, thermoclines are common, and temperatures can drop, especially at deeper levels. We recommend a 5mm wetsuit, possibly with a hood, due to these temperature variations and extended dive times.
• Visibility: Visibility can vary seasonally, often exceeding 30 meters during the dry season (December to May) and ranging from 15 to 25 meters during the wet season (June to November) due to plankton blooms that fuel the rich ecosystem.
• Certification: Due to the challenging conditions, including deep starts, strong currents, and the need for perfect buoyancy, an Advanced Open Water certification is required. Many operators also recommend a minimum of 100 logged dives for this technical dive site.

Marine Life Encounters

Bajo Alcyone is a magnet for pelagic species, offering breathtaking encounters:

• Scalloped Hammerhead Sharks: The main attraction! Divers will find hundreds of Scalloped Hammerhead Sharks (Sphyrna lewini) schooling at cleaning stations, creating an awe-inspiring spectacle as they stack up in the blue.
• Galápagos Sharks: We frequently encounter Galápagos Sharks (Carcharhinus galapagensis) patrolling the seamount.
• Whitetip Reef Sharks: Whitetip Reef Sharks (Triaenodon obesus) are a common sight, often seen resting or hunting around the pinnacle.
• Whale Sharks: During the wet season, particularly from June to August, the chances of encountering a majestic Whale Shark (Rhincodon typus) increase significantly.
• Giant Oceanic Manta Rays: Keep an eye out for Giant Oceanic Manta Rays (Mobula birostris) gracefully gliding through the water.
• Other Pelagics: Divers may also spot Silky Sharks, Marble Rays, and occasionally even Tiger Sharks, especially during peak hammerhead season. Large schools of jacks, tuna, and barracuda often fill the water column, adding to the vibrant ecosystem.

Hazards and Safety

This dive site presents significant challenges, primarily due to the strong currents and the depth. We emphasize the importance of following your instructor's guidance, maintaining excellent buoyancy control, and being prepared for negative descents. Surface marker buoys (SMBs) and dive computers are mandatory for all dives here.

Bajo Alcyone promises an unforgettable diving adventure for experienced divers seeking the thrill of massive pelagic encounters in a truly wild marine environment.