Dive sites in New Caledonia

Amedee Islet is located about 24 kilometres south of Noumea on the outer barrier reef. Daily tourist boats depart from Noumea's Moselle Bay marina and the crossing takes roughly 45 minutes. Several dive operators in Noumea run dedicated dive trips to the reef, and some combine them with the regular tourist catamaran service. The islet has a small restaurant and beach facilities but no overnight accommodation. Most divers do a morning two-tank trip and return to Noumea in the afternoon.

The banded sea kraits at Amedee are technically venomous but are exceptionally docile and have tiny mouths that make biting a human nearly impossible. They are not aggressive and will usually ignore divers completely as they hunt for small fish in coral crevices. In decades of diving at Amedee there have been no recorded envenomation incidents. The snakes breathe air and are frequently seen at the surface or resting on the beach. Simply give them space and avoid handling them, and they pose no practical danger.

Nautilus are deep-water creatures that live at depths of 200 to 500 metres during the day and rise to shallower depths at night. At Amedee, night dives on the outer reef slope sometimes encounter them at 25 to 35 metres after dark, particularly during the cooler months from June to September when the thermocline is shallower. Sightings are not guaranteed but occur regularly enough that Noumea dive operators advertise dedicated nautilus night dives. A torch with a red filter is recommended to avoid startling them.

The Prony Needle is a tower-like formation on the floor of Baie du Prony, created by the precipitation of minerals from alkaline hydrothermal springs. The process responsible is serpentinisation, a chemical reaction between the ultramafic rock of New Caledonia's ancient oceanic crust and seawater. This reaction produces highly alkaline water with a pH approaching twelve, along with hydrogen and methane gases. As the alkaline spring water meets the surrounding seawater, calcium carbonate and brucite minerals precipitate, slowly building the needle formation over thousands of years. The main needle rises from approximately thirty-five metres to within two metres of the surface. Several smaller formations exist nearby, and active venting is visible from some structures as shimmering water columns.

The Prony Needle dive is rated advanced due to the depth of the needle's base at thirty-five metres and the occasionally limited visibility in the bay. The dive itself is not technically difficult: there is minimal current, and the needle provides a clear vertical reference that eliminates navigation concerns. However, the unique chemistry of the site means that the alkaline water from the vents can cause skin irritation on exposed areas, and divers should avoid direct contact with actively venting areas. A minimum of thirty logged dives is recommended. Nitrox certification is advantageous for extended bottom time at the needle's base. Dry suit diving is not necessary as water temperatures remain between twenty-two and twenty-seven degrees.