Agdenes Lighthouse Reef
Trondheim Fjord · Norway
At the exposed mouth of Trondheimsfjorden where Atlantic swells meet calmer fjord water, the rocky reef around the Agdenes lighthouse is swept by powerful tidal exchanges that nourish some of the richest cold-water invertebrate communities in Norway. King crab are routine sightings, enormous rock sea urchin carpets the shallows, and the water clarity here regularly exceeds 25 m in winter — a benchmark dive for experienced cold-water divers.
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
3 to 18°C
Drysuit required
Month by month
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Water (°C) | 4 | 3 | 3 | 4 | 6 | 10 | 13 | 14 | 12 | 8 | 5 | 4 |
| Vis (m) | 18 | 20 | 20 | 15 | 12 | 10 | 8 | 8 | 10 | 15 | 18 | 18 |
| Current | Strong | Strong | Strong | Strong | Strong | Moderate | Moderate | Moderate | Moderate | Strong | Strong | Strong |
Your chances of seeing each animal
Three-Coloured Aeolis
Last confirmed Mar 15, 2026 · 6 records
Very likely
Most dives
Edible Sea Urchin
Last confirmed Jun 26, 2026 · 4 records
Likely
About 6 in 10 dives
Yellow Sea Slug Of ØRland
Last confirmed Mar 15, 2026 · 1 records
Likely
About 6 in 10 dives
Pink Coryphella
Last confirmed Jan 28, 2026 · 4 records
Likely
About 6 in 10 dives
Crowned Seaslug
Last confirmed Jan 14, 2024 · 1 records
Likely
About 6 in 10 dives
Atlantic Halibut
Last confirmed Aug 2, 2024 · 1 records
Sometimes
About 1 in 3 dives
Red King Crab
Expected
Known here, not yet in recent logs
Ballan Wrasse
Expected
Known here, not yet in recent logs
Gear