Nakanai Mountains

The Nakanai range runs along the interior of New Britain, a block of limestone lifted and cut by extremely high rainfall into one of the great karst landscapes: rivers disappear into shafts, enormous dolines drop hundreds of metres through the forest, and cave systems carry underground rivers of very high flow, including passages that rank among the largest by volume anywhere. Minye, Naré and Ora are among the named dolines, explored by French, Italian and other expeditions since the 1980s. The range is on Papua New Guinea's tentative World Heritage list as part of the Sublime Karsts. Reaching it means expedition logistics, landowner agreement and guides from the villages.

What you actually see

• The dolines - the vast sinkholes dropping through the forest.
• Underground rivers - the high-flow systems inside the karst.
• Cave passages - the very large chambers explored by expeditions.
• Rainforest karst - the limestone landscape under continuous forest.

When to go

May to October is marginally drier, but this is one of the wettest places on earth and flooding in the caves is a constant hazard. Expeditions take months to arrange with landowners and logistics.

Honest expectations

This is expedition caving country, not a visitor destination: no infrastructure, no marked routes, and access entirely dependent on landowner agreement. Cave flooding is lethal and rain is near constant. Costs and logistics are substantial.

Nearby

The north coast road lies below; Rabaul is northeast.