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Hotels, dive operators, gear, and how to get here are on the Rock Islands location page.
Overview
A natural cut through the barrier reef west of Ulong Island, often picked as Palau's signature drift. Enter at the channel mouth around 18-20 m where grey reef and whitetip sharks patrol the sandy runoff, hook in to a rocky ledge to watch the parade, then unhook and let the incoming current carry you down a coral-lined corridor past a 5-7 m wall of lettuce coral (Pavona) and schools of jacks, snapper, and barracuda. April-July full moons bring spawning aggregations of camouflage groupers.
Briefing note
Permit: requires the Rock Islands / Koror State permit (sold with Palau Pristine Paradise Environmental Fee at arrival). Strong currents — Advanced Open Water and reef-hook experience expected. Best on incoming tide; grouper spawning aggregations on full moons April-July.
What you'll see
6 species curated- year-roundGrey reef shark
- year-roundWhitetip reef shark
- seasonalCamouflage grouperPeak: Apr · May · Jun · Jul
- year-roundBigeye trevally
- year-roundChevron barracuda
- year-roundGreen turtle
Sightings evidence
1 record on file- high confidenceGrey reef shark
- 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 We deliberately do not publish a numeric '% chance of sighting' from this data.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
- iNaturalist — California Academy of Sciences & National Geographic Society
- IUCN Red List of Threatened Species — International Union for Conservation of Nature
- Wildbook (Sharkbook, Whale Shark, Manta Matcher) — Wild Me
- OBIS-SEAMAP — Duke University Marine Geospatial Ecology Lab / OBIS
- 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 | 28–29 °C | 20–30 m | strong |
| Feb | 28–29 °C | 20–30 m | strong |
| Mar | 28–30 °C | 25–30 m | strong |
| Apr | 28–30 °C | 25–30 m | strong |
| May | 29–30 °C | 20–30 m | strong |
| Jun | 29–30 °C | 15–25 m | strong |
| Jul | 29–30 °C | 15–25 m | moderate |
| Aug | 29–30 °C | 15–25 m | moderate |
| Sep | 29–30 °C | 15–25 m | moderate |
| Oct | 28–30 °C | 20–30 m | moderate |
| Nov | 28–30 °C | 25–30 m | strong |
| Dec | 28–29 °C | 25–30 m | strong |
Season calendar
Peak season highlighted · current month outlined
Gear for this site
Beyond the basic kit- Reef hook — Hook-in at the channel entrance is the standard technique to watch sharks and snappers without finning against the current.
- Surface marker buoy — Drift exits the channel into open water — operators require SMB for pickup.
Next step
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