Blue Hole
Kosrae · Federated States of Micronesia
Kosrae's Blue Hole is a vertical shaft that drops from 5 meters at the surface through a narrow chimney before opening into a dramatic cavern at 30 meters, with a sheer outer wall continuing well beyond recreational limits. Shafts of sunlight pierce the entrance at midday, illuminating clouds of glassy sweepers and silversides that pack the chimney walls. The outer drop-off beyond the hole's rim hosts grey reef sharks cruising the thermocline and large Napoleon wrasse patrolling the coral-encrusted lip.
Conditions
Depth
5 to 40 m
Advanced depths
Current
Usually still
Can pick up on the edge
Visibility
25 to 40 m
Clearest in the calm season
Water
27 to 30°C
3mm wetsuit
Month by month
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Water (°C) | 27 | 27 | 27 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 27 | 27 |
| Vis (m) | 15 | 15 | 20 | 20 | 20 | 25 | 25 | 25 | 20 | 15 | 15 | 15 |
| Current | Gentle | Gentle | Gentle | Still | Still | Still | Still | Gentle | Gentle | Moderate | Moderate | Gentle |
Your chances of seeing each animal
Tracey'S Damselfish
Last confirmed Apr 9, 2026 · 11 records
Sometimes
About 1 in 3 dives
Grey Reef Shark
Expected
Known here, not yet in recent logs
Napoleon Wrasse
Expected
Known here, not yet in recent logs
Silvertip Snapper
Expected
Known here, not yet in recent logs
Hawksbill Sea Turtle
Expected
Known here, not yet in recent logs
Giant Carpet Anemone
Expected
Known here, not yet in recent logs
Orangefin Anemonefish
Expected
Known here, not yet in recent logs
Caroline Islands Swiftlet
Expected
Known here, not yet in recent logs
Gear