Kong Lor Cave

The Nam Hin Boun river runs straight into the base of a limestone mountain and comes out roughly seven and a half kilometres later on the far side. A longtail boat with three passengers and two boatmen takes you through, engine echoing off walls you cannot see, head torches picking out a ceiling that in places lifts to something like a hundred metres. Twice the boat is dragged over shallow rapids and everyone walks. Midway there is a landing where a lit path leads through a chamber of stalactites, the only part of the trip where you get a sense of the scale around you.

What you actually see

• The tunnel - around seven and a half kilometres of river running clean through the mountain.
• The chamber - a lit walkway partway through, past stalagmites and flowstone, the one place the size becomes visible.
• The far exit - a green pool and forest at Ban Natane, where boats stop before turning back.
• The shallows - rapids where everyone gets out and the boat is pushed over the rock.

When to go

November to April is the dry season and the only reliable window: the water is low enough to pass and clear enough to see the bottom at the exits. In the wet months the river runs high and fast, and the cave closes for days or weeks at a time without notice. Mornings are cooler on the water and the village is quiet.

Honest expectations

The boat is open and low, and everything you carry will get wet; dry bags are worth having. It is genuinely dark, and the head torches provided are weak, so bringing your own is the single best thing you can do for the trip. The road in is long and rough, and most people stay overnight in the village rather than trying to do it from Thakhek in a day.

Nearby

The Thakhek Loop passes the turning, and Ban Natane at the far end has homestays for those continuing on foot.