Poor Knights Islands — Rikoriko Cave
Bay of Islands · New Zealand
Rikoriko is one of the largest sea caves in the world, carved into the volcanic tuff of the Poor Knights Islands Marine Reserve. A cathedral-sized chamber fills with filtered blue light at mid-morning. The walls are dense with golden zoanthids, purple urchins, and the endemic demoiselle. Outside the cave, schooling trevally and kingfish patrol the open water above kelp forests draped in orange and crimson nudibranchs.
Conditions
Depth
3 to 40 m
Advanced depths
Current
Can be moderate
Can pick up on the edge
Visibility
15 to 30 m
Clearest in the calm season
Water
15 to 22°C
7mm wetsuit
Month by month
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Water (°C) | 20 | 20 | 20 | 18 | 17 | 16 | 15 | 15 | 15 | 16 | 18 | 19 |
| Vis (m) | 20 | 20 | 25 | 25 | 20 | 15 | 15 | 15 | 18 | 18 | 20 | 20 |
| Current | Gentle | Gentle | Gentle | Still | Still | Moderate | Moderate | Moderate | Gentle | Gentle | Gentle | Gentle |
Your chances of seeing each animal
Purple Sea Urchin
Last confirmed Jun 11, 2026 · 18 records
Very likely
Most dives
Schooling Trevally
Last confirmed Jan 8, 2026 · 29 records
Likely
About 6 in 10 dives
Kingfish
Last confirmed Feb 26, 2026 · 21 records
Likely
About 6 in 10 dives
New Zealand Fur Seal
Last confirmed May 28, 2026 · 16 records
Likely
About 6 in 10 dives
Jewel Anemone
Last confirmed Dec 31, 2025 · 3 records
Likely
About 6 in 10 dives
Spotty
Last confirmed Jan 2, 2026 · 1 records
Likely
About 6 in 10 dives
Golden Zoanthid
Expected
Known here, not yet in recent logs
Endemic Demoiselle
Expected
Known here, not yet in recent logs
Gear