Thetford Reef is a horseshoe-shaped outer reef about 45 km off Cairns, spanning 2 km of scattered coral heads, sandy patches, and swim-throughs. Its sheltered position makes it a reliable alternative when rougher outer reefs are inaccessible. Snorkelers explore vibrant coral gardens at sites like Squirts, where giant clams, anemonefish, and butterflyfish abound, while the shallow back of Horseshoe offers a calm, protected lagoon. Morning conditions typically deliver the best visibility across this compact, biodiverse reef system.
Thetford Reef
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Wave Height 0.2 mSwell Period 5.5 sWind Speed 8.6 knPrecipitation 8.1 mmTidal Phase flood
Last evaluated
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Community contribution: submitted by Daniel
Know before you go
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Moderate risk: Marine stingers
Stinger season — box jellyfish and Irukandji are present in coastal and reef waters during the warmer months (November to May).
Low risk: Tidal currents
Strong tidal flows can run through the reef channels and swim-throughs, especially during spring tides.
Low risk: Trade wind chop
Southeasterly trade winds from June to September can create choppy surface conditions on the transit and at the reef.
Low risk: Exposed bommie swells
Exposed bommie sites like Dog's Bommie attract larger pelagic species and are only visited in calm weather.
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Getting in
Snorkel tour
Entry
Thetford Reef is located approximately 45 km east of Cairns, Queensland. It is only accessible by commercial tour boat; the journey takes about 90 minutes. Boats depart from the Cairns Marlin Marina. Popular operators include Passions of Paradise, Silverswift, Dreamtime Dive & Snorkel, and Pro Dive Cairns.
Parking & facilities
Paid parking is available under The Pier Marketplace at Marlin Marina in Cairns (approx. AUD $7 per day).
toilets
Tours range from approximately AUD $275 to $308 per person for day trips; liveaboard packages cost more.
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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