Rathlin Island
Ireland · Ireland
Rathlin Island sits at the northern tip of Ireland in the North Channel, swept by strong tidal currents that upwell cold, nutrient-rich Atlantic water and support extraordinary concentrations of basking sharks, ocean sunfish, and vast kelp forests. The island's basalt columns, sea caves, and dramatic wall dives plunge to 30 metres along its wave-battered northern coast. Summer months bring aggregations of basking sharks filtering plankton blooms just metres from the cliff faces, a spectacle few places in the world can match.
Conditions
Depth
5 to 35 m
Advanced depths
Current
Can be moderate
Can pick up on the edge
Visibility
8 to 15 m
Clearest in the calm season
Water
6 to 17°C
7mm wetsuit
Month by month
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Water (°C) | 7 | 6 | 6 | 7 | 9 | 11 | 13 | 14 | 13 | 11 | 9 | 7 |
| Vis (m) | 4 | 4 | 5 | 5 | 6 | 7 | 8 | 8 | 7 | 5 | 4 | 4 |
| Current | Strong | Strong | Strong | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Strong | Strong | Strong |
Your chances of seeing each animal
Common Eider
Last confirmed Jun 15, 2026 · 55 records
Almost always
Nearly every dive
Atlantic Grey Seal
Last confirmed May 25, 2026 · 25 records
Very likely
Most dives
Northern Fulmar
Last confirmed Jul 1, 2026 · 39 records
Very likely
Most dives
Edible Crab
Last confirmed Jun 16, 2026 · 14 records
Very likely
Most dives
Razorbill
Last confirmed Jun 9, 2026 · 27 records
Likely
About 6 in 10 dives
Black-Legged Kittiwake
Last confirmed Jul 1, 2026 · 22 records
Likely
About 6 in 10 dives
Basking Shark
Last confirmed Jan 15, 2024 · 1 records
Sometimes
About 1 in 3 dives
Ocean Sunfish
Expected
Known here, not yet in recent logs
Gear