Petaj Mooring is a premier snorkel and dive site on Milln Reef, an outer Great Barrier Reef ribbon reef about 50 km east of Cairns. This protected mooring sits on the reef edge where the sandy bottom meets vibrant coral walls, offering clear waters (15-20 m visibility) and easy access to abundant marine life. The site is famed for resident green turtles and white-tip reef sharks that patrol the bommies, along with colourful coral gardens of staghorn and plate corals. As a Green Zone (no-take area), the reef remains pristine and teeming with fish, making it a favourite for both novice and intermediate snorkelers.
Petaj Mooring
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Showing last known conditions
Wave Height 0.1 mSwell Period 6.4 sWind Speed 8.8 knPrecipitation 8.4 mmTidal Phase flood
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Community contribution: submitted by Daniel
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Moderate risk: Marine Stingers (Seasonal)
Stinger season on the northern Great Barrier Reef brings potential for marine stingers (box jellyfish) during the warmer months.
Low risk: Mild Reef Currents
Mild currents can develop around the reef edge and bommies, especially during tidal changes.
Low risk: Boat Traffic
Boat traffic in the vicinity of mooring area; snorkelers should stay aware of tour vessels approaching and departing.
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Getting in
Snorkel tour
Entry
Milln Reef lies approximately 50 km east of Cairns. Petaj Mooring is a dedicated public mooring on the reef's outer edge, accessible only by boat. Full-day snorkel and dive tours from Cairns and Port Douglas visit this site regularly.
Parking & facilities
Park at the Cairns Marina or Port Douglas Marina (paid parking available). Tours depart from the marina terminals.
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About this data
- Conditions last evaluated
- Spot data last updated
- Data sources
- Open-Meteo (marine & weather conditions), tide predictions via UTide, community contributors (descriptions, hazards, marine life).
- License
- Spot content licensed under CC BY-SA 4.0. How's the Spot is open source.
Weather & swell ┬╖ Open-Meteo marine & weather APIs Tides ┬╖ UTide harmonic analysis Sea & safety ┬╖ community reports