Admiralty Anchor

Admiralty Anchor (Coral Sea)

Welcome to Admiralty Anchor, an exhilarating dive site nestled on Osprey Reef's southern and western flank in Australia's remote Coral Sea Marine Park. This isolated seamount, approximately 350 km from Cairns, boasts crystal-clear waters and dramatic underwater topography, making it a premier destination for advanced divers seeking thrilling encounters.

Dive Site Features

Admiralty Anchor is named for an old admiralty-style anchor wedged into a gutter, a unique focal point within a maze of gutters, ridges, and bommies. Divers will find an intricate network of swim-throughs and caves, offering exciting exploration opportunities. The reef top begins around 5 meters, descending through a labyrinth of coral formations to about 35 meters, where it then drops off dramatically into a wall plunging to depths exceeding 1000 meters. While the wall itself offers less to see, the shallower reef and sandy slopes provide an abundance of marine life. Visibility here is often phenomenal, frequently rising above 40 to 60 meters.

Marine Life

Admiralty Anchor is renowned for its vibrant pelagic action and diverse reef inhabitants. Divers can expect close encounters with numerous Whitetip Reef Sharks (Triaenodon obesus) and Grey Reef Sharks (Carcharhinus amblyrhynchos) patrolling the reef. Keep an eye out for graceful Reef Manta Rays (Mobula alfredi) and Spotted Eagle Rays (Aetobatus narinari) cruising in the blue. On the sandy bottom, we often find extensive colonies of shy Spotted Garden Eels (Heteroconger hassi) swaying in the current. Giant Trevally (Caranx ignobilis) are frequently seen, along with the striking Red Lionfish (Pterois volitans) tucked into ledges. Look closely, and you might spot the impressive Feather Star (Comanthina schlegeli), with one particularly large specimen, reportedly over a meter high, best observed when open at night. This dive site is also popular for night dives, offering a different perspective on its nocturnal residents.

Diving Conditions

• Difficulty: Advanced
• Certification Required: Advanced Open Water certification is essential for this dive site due to its challenging conditions.
• Depth: Divers will explore depths typically ranging from 5 m to 35 m, with the outer wall dropping to over 1000 m.
• Current: Currents at Admiralty Anchor are variable and can range from mild to strong, particularly with tidal lagoon-to-ocean sweeps. Excellent buoyancy control is advised.
• Water Temperature: The water temperature generally ranges from 22°C in winter to a warm 29°C in summer.
• Hazards: Strong currents, significant depth, and the potential for decompression obligation are key hazards at this remote dive site. We recommend careful dive planning and adherence to your training.