Xe Bang Fai River Cave

The Xe Bang Fai river disappears into the Hin Nam No karst and runs underground for several kilometres through a passage whose dimensions are the reason cavers come from a long way to see it. Sections are over a hundred metres wide and comparably high, which means head torches simply fail to reach the walls. A survey expedition mapped it properly in 2008 and the numbers put it among the largest active river cave passages recorded. Trips run by kayak and on foot, camping at the entrance, and are organised rather than turned up to.

What you actually see

• The main passage - chambers wide and high enough that a torch beam reaches nothing.
• The formations - terraced rimstone pools and columns on the ledges above the water.
• The river - the Xe Bang Fai itself, entering at one end of the mountain and reappearing at the other.
• The approach - jungle and karst walking to reach an entrance with no road to it.

When to go

December to March only. The cave is a working river passage and it floods hard in the wet season, which puts it out of reach from roughly May to October. Even in the dry months a heavy upstream storm can raise the level enough to cancel a trip at short notice.

Honest expectations

This is an expedition rather than an excursion: multiple days, camping, swimming, and long walks in heat. It is run through licensed operators and cannot be done independently. Anyone uncomfortable in deep water or in total darkness will not enjoy it, and the cost is high by Lao standards because the logistics genuinely are.

Nearby

Hin Nam No National Park surrounds the cave, and Kong Lor is the easier cave trip in the same province.