Meet the site
Phil's Reef is a patch reef on Agincourt Reef No. 3 that the Silverseries crew describe as having a spectacular array of corals, with huge plate corals providing perfect ambush grounds for groper. It is a compact site with a maximum depth around 16 m, which makes it easy to explore thoroughly in a single dive. The defining feature is the plate coral. Great tiers of Acropora plates and tables spread out from the reef like shelves, some several metres across, creating shaded caves beneath. Large groper and coral trout use the shade to hide and ambush passing fish, and whitetip reef sharks often rest on the sand beneath the biggest plates. Hussar snapper, pink with a yellow stripe, school around the reef in loose groups. On the sand margins blue-spotted lagoon rays lie half-buried and flick away as divers approach. Giant clams sit in the reef with mantles of electric blue, green and brown, and cuttlefish are common, hovering near coral heads and flashing colour changes. The coral top is shallow enough for snorkellers to see much of this, including the clams. Because the reef is small and roughly circular, navigation is simple: you circle it deep, then circle it again shallow, keeping the reef on the same shoulder. The relaxed profile suits new divers and it is a good site for anyone wanting to practise buoyancy near fragile coral – the plates are easily broken, so keep fins well clear. Visibility usually runs 15 m or more. For photographers the combination of layered plate coral and fish sheltering beneath makes excellent wide-angle compositions, and the cuttlefish and clams reward macro work. Phil's Reef is a gentle, rewarding dive and a nice contrast to the walls and drifts elsewhere on the Agincourt complex. Not to be confused with Phil's Backside, a deeper nearby site with sloping coral and bommies.
What you might see
Queensland groper, coral trout, whitetip reef sharks, hussar snapper, blue-spotted lagoon rays, giant clams, cuttlefish, plate and table corals
Location
A patch reef on Agincourt Reef No. 3 known for its huge plate corals and giant clams.
Facilities nearby
Departs Crystalbrook Superyacht Marina, Wharf Street, Port Douglas – car parking, toilets, cafes and restaurants at the marina; dive shops in town for gear hire and air
Before you make plans
Conditions, access and operator schedules can change. This is a location guide, not a dive plan. Ask a local operator about current conditions and suitability for your training and experience.
Sources & further reading
silverseries.com.auposeidon-cruises.com.auRecord updated 26 Sept 2026. Source claims are being reviewed.