- Where
- Luang Prabang Province,
northern Laos - Coordinates
- 19.7492° N
101.9917° E - From town
- About 30 km south-west
of Luang Prabang - Height
- Main drop 60 m (Wikipedia);
140 m overall (Kiernan, 2009) - The steps
- Tufa: limestone laid
down by the water - Bear centre
- Free the Bears, with the Lao
Department of Forestry, 2003 - Swimming
- In the signposted pools only
Out of town in the back of a little truck, past rice fields and novices in orange robes, then up through wet green forest where black bears with pale moons on their chests dozed in the shade. Then the pools: milky blue, stepping down the hill one into the next over pale stone. I sat on an edge with my sticky rice and could not name the colour.
The short answer
Kuang Si Falls, or Tat Kuang Si, is a multi-tiered waterfall in Luang Prabang Province, northern Laos. Wikipedia puts it about 29 kilometres south of the town of Luang Prabang, and Laos’s national tourism site about 30 kilometres south-west. The falls begin in shallow pools high on a steep, forested hillside and lead down to a main drop that Wikipedia gives as 60 metres; Kevin Kiernan’s survey of the karst of Laos, published in Acta Carsologica in 2009, gives the waterfall as 140 metres high, a figure that takes in the cascades as a whole. The river is the Nam Si, which Wikipedia says rises about 10 kilometres upstream. Below the main drop the water steps down through a chain of milky blue pools, some of them open for swimming, and beside the path at the bottom stands the Tat Kuang Si Bear Rescue Centre.
Why it's worth knowing
Most waterfalls wear their rock away. This one has built its own. Kiernan’s survey describes Tat Kuang Si as cascading over a massive accumulation of tufa on the western side of the Phu Phaxang Noy karst massif, the limestone upland whose other side feeds the Tat Sae falls. Tufa is a freshwater limestone. In Wikipedia’s account of its geology, it forms when water rich in dissolved calcium carbonate loses carbon dioxide to the air, as water does when it tumbles over a fall, so that the carbonate comes out of solution as stone; deposits concentrate at waterfalls, where the flow speeds up, and can grow into barrages across a stream several metres high.
So the pale rims that hold each pool at Kuang Si are not old rock the river has cut down to. They are stone the river has laid down.
What gives the pools their colour is a different question, and this entry has not found a study that answers it for Kuang Si. Guidebooks and tour operators put the blue down to fine particles of calcium carbonate in the water scattering sunlight. That is an explanation borrowed from other limestone waters, not a measurement made here, and this entry does not offer it as settled.
The field notes
Bears beside the path
The charity Free the Bears says that in 2003, in collaboration with the Lao Department of Forestry, it was given permission to build the Tat Kuang Si Bear Rescue Centre next to a small government rescue centre beside the falls. It became the charity’s first sanctuary in Laos: three bear houses with room for 25 bears, home to more than 20 sun bears and moon bears, or Asiatic black bears, taken from bile farms and the illegal wildlife trade. The Lao national tourism site notes that visitors walk past the enclosures on the forest path to the falls, with no separate ticket. In 2013, the charity says, its small clinic in the park performed the world’s first neurosurgery on a bear, relieving a moon bear called ChamPa of hydrocephalus; the claim to be first is the charity’s own.
Where the bears come from
In late 2017 Free the Bears opened a larger sanctuary, the Luang Prabang Wildlife Sanctuary, in a valley about 8 kilometres from the falls. In June 2026 the charity reported that, with the Lao authorities, it had rescued 27 young moon bears from an illegal bile farm registered as a zoo, and moved them to that sanctuary; it called the operation the largest bear-farm rescue in South-East Asia, and the conservation news site Mongabay reported it the same month. The bears by the falls are the smaller, older part of that work.
Lunch in a leaf
In 2022 Laos’s national tourism authority reported that Kuang Si had won an ASEAN Sustainable Tourism Award, after the local authorities took measures against the spread of Covid-19 and encouraged the vendors at the site to use biodegradable packaging such as banana leaves. The same report says facilities were upgraded and that an electric shuttle now runs from the ticket station to the falls and viewpoints.
A shallow pool below the cascades, a fallen trunk lying across the milky blue water, December 2019.
Photograph: Balon Greyjoy · CC0 · cropped
Water spilling over curved lips of tufa, the limestone the river lays down as it flows, January 2022.
Photograph: Basile Morin · CC BY-SA 4.0
A broad tufa ledge in the lower cascades, November 2017.
Photograph: Jakub Hałun · CC BY-SA 4.0
A rescued Asiatic black bear (moon bear) dozing in a hammock at the rescue centre beside the falls.
Photograph: istolethetv · Two bile bears at The Tat Kuang Si bear rescue centre, Laos · CC BY 2.0
Rainy-season floodwater running brown through the forest at Kuang Si, August 2018.
Photograph: Christophe95 · CC BY-SA 4.0 · cropped
- Walk past the bears quietly and feed them nothing. Their keepers know what they need.
- Go early, before the vans, and have the top pools to yourself for a while.
- Keep to the marked paths in the hills above, however tempting the shortcut.
- Eat your lunch out of a leaf, from the stalls at the gate.
- Swim in one pool only. (Swam in one pool. Then the one below it, to compare. Then the one below that, for fairness. The page for this item is still damp.)
A lip of tufa. The curved rim of one of the pools below the main drop at Kuang Si: a lip of pale, porous stone over which the water spills into the next pool down. It is tufa, a freshwater limestone that forms when carbonate minerals come out of solution in flowing water, and the whole waterfall cascades over a massive accumulation of it. The steps the water falls down were made by water.
Tally, in the marginStairs made by the thing walking down them. I sat on one all afternoon eating my lunch, and never thought to thank the builder, who was going past my feet the whole time.
Getting there
How to get there. Luang Prabang has an international airport about 4 kilometres from the town and, by Wikipedia’s account, a station on the Laos–China railway about 15 kilometres out, with trains to Vientiane and through Boten to Kunming. From town to the falls, Laos’s national tourism site describes shared tuk-tuks and vans or a private vehicle; allow about an hour each way.
At the gate. Entry is by ticket at the gate, priced in kip, and prices change; the national tourism site says the bear rescue centre is on the path inside and needs no separate ticket, and that an electric shuttle runs from the ticket station. Go early in the day.
Swimming. Swimming is allowed in the pools signposted for it, with changing rooms nearby, in the tourism site’s description. A trail climbs beside the main drop to more pools at the top.
How to be there. Walk past the bears quietly and feed them nothing. Buy food from the stalls at the gate rather than carrying plastic in.
Safety. The United States has Laos at Level 2, exercise increased caution, because of crime, unrest and unexploded ordnance. Luang Prabang province is among those named for increased caution because of crime and because of unexploded ordnance left from the Indochina War: keep to marked paths in the hills. The advisory asks travellers to reconsider travel to Xaisomboun province and to avoid the Special Economic Zones, especially the Golden Triangle zone in Bokeo and the Boten zone.
Mark this place
Common questions
Why is the water at Kuang Si Falls blue?
Nobody has published a study made at Kuang Si Falls in Laos that this entry could find. The falls run over tufa, a limestone deposited from water rich in calcium carbonate, according to Kevin Kiernan’s 2009 survey of the karst of Laos. Guidebooks and tour operators attribute the milky blue to fine carbonate particles scattering sunlight, an explanation borrowed from other limestone waters.
How tall is Kuang Si Falls?
Wikipedia gives the main drop of Kuang Si Falls, near Luang Prabang in Laos, as 60 metres. Kevin Kiernan’s survey of the karst of Laos, published in Acta Carsologica in 2009, gives the waterfall as 140 metres high, which counts the whole cascade of tiers and pools below the main drop as well as the drop itself.
How far is Kuang Si Falls from Luang Prabang?
Kuang Si Falls is about 30 kilometres from the town of Luang Prabang in northern Laos: Wikipedia says 29 kilometres to the south, and Laos’s national tourism site about 30 kilometres to the south-west. Visitors go by shared tuk-tuk or van, or by private vehicle, and the drive takes about an hour each way.
Can you swim at Kuang Si Falls?
Yes, in the pools signposted for swimming. Laos’s national tourism site says Kuang Si Falls near Luang Prabang has signs marking the swimming pools, with changing rooms nearby, and a trail up to more pools at the top of the main drop. Other pools are not for swimming.
What is the bear rescue centre at Kuang Si Falls?
The Tat Kuang Si Bear Rescue Centre, beside Kuang Si Falls near Luang Prabang in Laos, was built from 2003 by the charity Free the Bears with the Lao Department of Forestry, next to a small government rescue centre. It has three bear houses for up to 25 bears and cares for more than 20 sun bears and moon bears rescued from bile farms and the wildlife trade.
What kind of bears are at Kuang Si Falls?
Moon bears, also called Asiatic black bears, and sun bears. Free the Bears, which runs the Tat Kuang Si Bear Rescue Centre beside the falls in Laos, says the bears there were rescued from bear-bile farms and the illegal wildlife trade. The charity’s larger Luang Prabang Wildlife Sanctuary, opened in late 2017, lies about 8 kilometres away.
What is tufa?
Tufa is a freshwater limestone that forms when calcium carbonate comes out of solution in unheated rivers, springs or lakes, often as the water loses carbon dioxide tumbling over falls. It builds up fastest at waterfalls and can grow into dams across a stream. Kevin Kiernan’s 2009 survey of Laos describes Kuang Si Falls as cascading over a massive accumulation of it.
Is it safe to visit Kuang Si Falls?
The United States has Laos at Level 2, exercise increased caution, because of crime, unrest and unexploded ordnance, and names Luang Prabang province, where Kuang Si Falls lies, among those needing increased caution for crime and for unexploded ordnance. Keep to marked paths in the hills. The advisory’s only Reconsider Travel area is Xaisomboun province.