Planning a trip?
Hotels, dive operators, gear, and how to get here are on the Poor Knights Islands location page.
Overview
Largest sea cave in the southern hemisphere by volume. You can enter by boat then drop down for a circular dive around the cave mouth. Walls fluoresce under UV light; the cave roof rings with whale song during humpback migration.
What you'll see
3 species curated- year-roundStingray
- year-roundSnapper
- year-roundCrayfish
Sightings evidence
1 record on file- high confidenceStingray
- Last confirmed
- Apr 2026
- Recent records
- 130 within 10 km
Sources & methodology
How we summarise this
We aggregate confirmed occurrence records from GBIF and OBIS within a fixed radius of each dive site. Occurrence records confirm presence and reveal seasonality clustering, but they DO NOT measure per-dive probability — there is no eligible-effort denominator. We deliberately do not publish a numeric '% chance of sighting' from this data.
Sources
- Global Biodiversity Information Facility — GBIF Secretariat
- Ocean Biodiversity Information System — IOC-UNESCO
- OBIS-SEAMAP — Duke University Marine Geospatial Ecology Lab / OBIS
- iNaturalist — California Academy of Sciences & National Geographic Society
- IUCN Red List of Threatened Species — International Union for Conservation of Nature
- WoRMS — World Register of Marine Species — Flanders Marine Institute (VLIZ)
- FishBase — FishBase Consortium
- Atlas of Living Australia — CSIRO / GBIF Australia
- REEF Volunteer Fish Survey — Reef Environmental Education Foundation
Conditions
| Month | Water | Visibility | Current |
|---|---|---|---|
| Jan | 19–21 °C | 15–30 m | moderate |
| Feb | 20–22 °C | 15–30 m | moderate |
| Mar | 20–22 °C | 15–30 m | moderate |
| Apr | 19–21 °C | 15–30 m | moderate |
| May | 17–19 °C | 15–30 m | moderate |
| Jun | 16–18 °C | 15–30 m | moderate |
| Jul | 15–17 °C | 15–30 m | moderate |
| Aug | 14–16 °C | 15–30 m | moderate |
| Sep | 14–16 °C | 15–30 m | moderate |
| Oct | 15–17 °C | 15–30 m | moderate |
| Nov | 16–18 °C | 15–30 m | moderate |
| Dec | 18–20 °C | 15–30 m | moderate |
Season calendar
Peak season highlighted · current month outlined
Gear for this site
Beyond the basic kit- 5mm wetsuit — New Zealand water is cool — 14-22C year-round.
- Dive light — Cave interior is dark; UV light brings out fluorescent walls.
Next step
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Hotels, liveaboards, dive operators, gear recommendations, and travel logistics for the whole region.
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