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Hotels, dive operators, gear, and how to get here are on the Cocos Island location page.
Overview
Cluster of jagged pinnacles off Cocos's northwest corner, streaked with guano that gives the rock its name. Drop down a wall to 20–25 m and hold position at the barberfish cleaning station — scalloped hammerheads queue overhead in schools that can number in the hundreds, sliding in one at a time to be cleaned. Galapagos sharks, marbled rays, and bigeye trevally fill the blue between passes. Strong current and surge are the price of admission.
Briefing note
Cocos Island National Park is permit-controlled and accessible only via licensed liveaboards. Park ranger station at Wafer Bay. AOW + 50 logged dives is the de facto minimum across operators; many require 100+. Hammerhead population has declined sharply since the 2000s but the cleaning-station behavior at Dirty Rock remains the most reliable encounter in the Eastern Pacific.
What you'll see
7 species curated- year-roundScalloped hammerhead
- year-roundGalapagos shark
- year-roundWhitetip reef shark
- year-roundMarbled ray
- year-roundBigeye trevally
- seasonalWhale sharkPeak: Jun · Jul · Aug · Sep · Oct · Nov
- year-roundBarberfish
Sightings evidence
1 record on file- high confidenceScalloped hammerhead
- Last confirmed
- Nov 2025
- Recent records
- 65 within 50 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 We deliberately do not publish a numeric '% chance of sighting' from this data.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
- 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
- iNaturalist — California Academy of Sciences & National Geographic Society
- 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 | 25–27 °C | 20–30 m | moderate |
| Feb | 26–28 °C | 20–30 m | moderate |
| Mar | 27–28 °C | 25–35 m | moderate |
| Apr | 27–28 °C | 25–35 m | moderate |
| May | 26–28 °C | 20–30 m | moderate |
| Jun | 25–27 °C | 15–25 m | strong |
| Jul | 24–27 °C | 10–20 m | strong |
| Aug | 24–27 °C | 10–20 m | strong |
| Sep | 24–27 °C | 10–20 m | strong |
| Oct | 25–27 °C | 10–20 m | strong |
| Nov | 25–27 °C | 15–25 m | strong |
| Dec | 25–27 °C | 20–30 m | moderate |
Season calendar
Peak season highlighted · current month outlined
Gear for this site
Beyond the basic kit- Temperate-grade wetsuit — Thermocline can drop into the low 20s°C even during the warm-water months — a 5 mm full suit is the working minimum.
- Reef hook — Standard practice is to hook into dead substrate at the cleaning station ledge and hold position while hammerheads queue overhead. Saves air and reduces silting.
- Nitrox certification — Hammerhead action is at 20–25 m and divers stay there for the whole dive; EAN32 meaningfully extends bottom time. All Cocos liveaboards offer nitrox.
- SMB and reel — Surface intervals happen well offshore of the main island and current can push you away from the pinnacles fast — every diver carries their own marker.
Next step
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