Papua New Guinea

Papua New Guinea occupies the eastern half of one of the world's largest islands, and the seas that surround it are among the richest on the planet. This is not convenient diving — logistics are complex, infrastructure is limited outside established dive centres, and costs are high. For the diver prepared for all of this, PNG delivers an experience that few destinations can match.

Kimbe Bay, on the north coast of West New Britain, is the jewel. A wide, sheltered bay fringed with seamounts and coral walls, Kimbe Bay contains over 860 species of reef fish — among the highest recorded densities in the Coral Triangle. The seamounts attract schooling scalloped hammerheads, whale sharks, and silvertip sharks. The shallow reefs offer macro life so dense that a single bommie can keep a photographer occupied for an entire dive.

Rabaul, the volcanic harbour town on New Britain's northern tip, is WWII wreck territory. The harbour holds the remains of the Japanese South Seas Fleet — destroyers, freighters, Zero fighters, and landing barges, all sunk during Allied bombing raids in 1944. Visibility in the harbour is variable, but the marine life colonising the wrecks — soft corals, glass fish, sea fans — is extraordinary.

Milne Bay, at the country's eastern tip, was where the style of diving known as 'muck diving' was first described by Bob Halstead in the 1980s. Rhinopias scorpionfish, blue-ringed octopus, mimic octopus — creatures that exist in photographs but seem too improbable to find in real life appear here on sand slopes of unremarkable appearance.

Best season: May–October for Kimbe Bay and Milne Bay. The wet season (November–April) brings rougher seas but fewer boats and lower prices.