Milne Bay

The trip is the boat. Divers join at Alotau and the day settles into three or four dives, with a dusk or night dive added most evenings. Skippers work the sheltered bays when the weather closes in and move out to reef and wall sites when it opens, so the running order is rarely fixed before departure. Longer crossings between anchorages are normally done overnight, which keeps diving time close to wherever the boat woke up.

Underwater the ground is mostly black sand and fine silt, running down from the beaches in gentle slopes broken by seagrass, rubble, sunken timber and the occasional isolated coral head. Visibility on those slopes is modest by tropical standards and the bottom lifts easily, so trim and fin control matter more than depth or air consumption. There is proper reef here too — walls, drop-offs and current-touched points — which is what the boats use to break up a week of sand.

The core experience is slow and guide-led: a whole dive spent covering a few square metres of slope while a spotter works ahead of you, turning up ornate ghost pipefish, frogfish parked against sponges, tiny shrimp on whip corals and juvenile fish doing convincing impressions of leaves. Dusk dives over rubble are timed for mandarinfish rising off the bottom in the last of the light, and on the reef sections gorgonians hold pygmy seahorses, keeping the photography macro at a slightly larger scale.

It rewards patience over technique, and suits divers content to spend a whole dive inside one small patch of slope, ideally with a camera. The intermediate rating reflects buoyancy over silt and the rhythm of long days at sea rather than hard conditions, since current is usually gentle. Anyone set on blue water and big schools all week will be better served elsewhere in Papua New Guinea, and anyone prone to seasickness should weigh up the overnight passages first.