Admiralty Dive Site sits at the southern entrance of Osprey Reef's lagoon in the remote Coral Sea, off Cape York. This spectacular open-ocean reef features a maze of large caves, swim-throughs, and sandy gullies that rise from the abyss (1000m+) into the shallow lagoon. The site is named for an old marine anchor resting in one of the swim-throughs — a haunting relic. Its terrain provides shelter to sleeping whitetip reef sharks and tawny nurse sharks, while grey reef sharks, manta rays, and octopus patrol the drop-offs. Accessible only via liveaboard, it offers pristine, untouched reef diving far from the crowds.
Admiralty Dive Site
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Showing last known conditions
Wave Height 0.0 mSwell Period 3.1 sWind Speed 4.4 knPrecipitation 0.6 mmTidal Phase flood
Last evaluated
DANGER: Explicit Risks Present
Admiralty Dive Site has hazards marked as danger. Entering the water here means you may face serious risks to your personal safety.
- Remote location danger
Located in the remote Coral Sea far from emergency medical facilities — evacuation is hours away.
The spot
Community-maintained
Community contribution: submitted by Daniel
Know before you go
Logged by the community, confirmed by mods
High risk: Remote location
Located in the remote Coral Sea far from emergency medical facilities — evacuation is hours away.
Moderate risk: Strong ocean currents
The site sits at a lagoon entrance where currents can be strong and unpredictable, especially on the drop-off beyond 30m.
Moderate risk: Deep water adjacent
The reef wall drops to over 1000m immediately beyond the reef edge — depth awareness is critical.
Low risk: Cave/swim-through hazards
Numerous large caves and swim-throughs require good buoyancy control and careful navigation to avoid disorientation or entanglement.
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Getting in
Boat
Entry
Admiralty Dive Site is located on Osprey Reef, approximately 350km northeast of Cairns in the Coral Sea. It is only accessible via multi-day liveaboard dive vessels departing from Cairns or Cooktown. No land-based access exists.
Parking & facilities
Not applicable — no land access. All trips depart from Cairns or Cooktown ports.
Access is via liveaboard charters only. Typical 4-7 day trips range from AUD $2,000-$4,000 per person depending on vessel and itinerary.
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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