Bajo Alcyone
Cocos Island · Costa Rica
Submerged seamount 25 m below the surface, rising from the deep. Hammerhead schools in the hundreds patrol the up current edge. Cold thermocline, surge, and current — the most famous dive in the Eastern Pacific.
Conditions
Depth
25 to 40 m
Advanced depths
Current
Often strong
Can pick up on the edge
Visibility
10 to 20 m
Clearest in the calm season
Water
24 to 28°C
Temperate wetsuit
Month by month
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Water (°C) | 25 | 26 | 27 | 27 | 26 | 25 | 24 | 24 | 24 | 25 | 25 | 25 |
| Vis (m) | 15 | 15 | 20 | 20 | 15 | 10 | 10 | 10 | 10 | 10 | 10 | 15 |
| Current | Strong | Moderate | Moderate | Moderate | Moderate | Strong | Strong | Strong | Strong | Strong | Strong | Strong |
Your chances of seeing each animal
Whitetip Reef Shark
Last confirmed Feb 2, 2026 · 39 records
Very likely
Most dives
Mexican Hogfish
Last confirmed Feb 2, 2026 · 33 records
Very likely
Most dives
Guineafowl Puffer
Last confirmed Apr 10, 2026 · 24 records
Very likely
Most dives
Scalloped hammerhead
Last confirmed Mar 22, 2026 · 58 records
Very likely
Most dives
Cocos Wrasse
Last confirmed Jan 27, 2026 · 20 records
Likely
About 6 in 10 dives
Galapagos shark
Last confirmed Jan 29, 2026 · 2 records
Sometimes
About 1 in 3 dives
Silvertip shark
Last confirmed Dec 4, 2024 · 2 records
Sometimes
About 1 in 3 dives
Whale shark
Expected
Known here, not yet in recent logs
Gear
Basic kit
For this site