Tu San canyon is the gorge the Nho Que River has cut below Ma Pi Leng Pass, with limestone walls usually given as 700 to 900 m high and a narrow section about 1.7 km long. Vietnamese sources call it the deepest canyon in Vietnam and South-East Asia. You can see it from a motor boat on the river or from the lookouts and cliff trail above.
The boat is the only way to be inside it. Trips leave a dock by the Nho Que 1 dam, run up into the gorge and back in 45 to 60 minutes, and cost 150,000 VND (~$6) per adult. The best light on the walls is early morning or after about 15:00.
Tu San from the boat and from the rim
Our trips pair the canyon lookouts on Ma Pi Leng with a boat into Tu San, with a licensed local guide and your own car between them.
★Ha Giang Loop by Private Car — 3 DaysThree days around the Ha Giang Loop in your own car, from Ha Giang city — Heaven Gate, Lung Cu, the Sky Path on Ma Pi Leng and a private boat on the Nho Que. · 3 days, 2 nightsSee the tour →Ha Giang Loop from Hanoi — 4 Days by Private CarDoor to door from Hanoi: four days on the Ha Giang Loop with your own car, a licensed local guide and a good hotel every night. · 4 days, 3 nightsSee the tour →What the canyon is
Tu San is where the Nho Que, crossing the Dong Van plateau from China, meets the thickest limestone of the karst and cuts straight down through it. The river has worked its way into carbonate rock that dissolves as well as erodes, which is why the walls are near vertical rather than sloping: there is little loose scree, just bare cliff with ledges and overhangs.
The gorge straddles the old Dong Van and Meo Vac districts, below the communes of Pai Lung and Xin Cai, directly under the Ma Pi Leng road. Together with the pass it has been a national scenic monument since 2009, and it is one of the signature sites of the Dong Van Karst Plateau Global Geopark, listed by UNESCO in 2010.
How deep it really is
The numbers repeated for Tu San vary from source to source, and it helps to know which are firm.
| Figure | What sources give | How solid it is |
|---|---|---|
| Height of the walls | 700–800 m in most travel sources, 700–900 m in the provincial press, “nearly 1 km” in some | Consistent in range; no single surveyed figure published |
| Length of the narrow section | About 1.7 km | Widely repeated and consistent |
| “Deepest in South-East Asia” | Vietnamese official and press sources | A national claim; we found no international survey ranking it |
What is not in doubt is the scale when you are in it. From the water the walls rise straight out of the lake, and in a longboat seating about 18 you are a very small thing at the bottom of a very tall slot.
What you see from the boat
The boats start on the wider water near the dam, where the valley is more open. Heading upstream, the sides close in and steepen until the lake is running between sheer limestone walls with only a strip of sky above. That narrow section is the reason for the trip; the open water before it is the approach, and the boat comes back the same way, so you see each wall twice in different light.
Sit where you can look up rather than ahead. The scale of Tu San is vertical: the photographs that work are the ones that fit a wall from the waterline to the rim, and a phone held in landscape rarely does.
Time it for early morning or mid-afternoon if you can. At midday the sun is high enough to flatten the walls and bleach the green out of the water; lower light picks out the texture and leaves one side in shade. Nho Que boats run from 7:00 to 18:30 all year but stop after heavy rain or when the reservoir runs high. If the boat is off on your day, your guide swaps in the canyon viewpoints and a longer walk on the Sky Path.
How the dam changed the canyon
Tu San was not always a place for boats. Before the Nho Que 1 plant began generating in 2017, the river ran fast through the gorge, and motor-boat trips only became a routine outing once the dam had calmed the water. The dam raised and slowed the water, and in doing so made the calm motor-boat trip possible, gave the lake its jade colour, and drowned the lower part of the walls along with whatever rapids the river had in the narrow section.
It also means the canyon now behaves like a reservoir. In a dry spell the water is clear and green; after heavy rain upstream it turns brown and the level rises, and the operator stops the boats. Our Nho Que River guide covers the river, the dams and the boat fares in more detail.
Seeing it from above
The rim gives the other half of the picture: the whole bend of the river seen from high on the cliff. Three kinds of place do this best.
| Where | The view | Effort |
|---|---|---|
| Canyon lay-bys on the pass | Straight down into the gorge and the reservoir | None; a car stops there |
| Tu San pavilion on the Sky Path | Down into the canyon from the cliff trail above the road | A walk of an hour or more |
| Cafe terraces on the pass | Much the same view as the lay-bys, with a seat and a drink | None; some charge for entry |
The cliff trail is described in our Sky Path guide, and the order of the roadside stops is in the Ma Pi Leng Pass guide.
Tu San on our trips
Both our tours see the canyon from above and from the water on the same day. On the three-day Ha Giang Loop it is day two, between the Ma Pi Leng lookouts and lunch in Meo Vac; on the four-day trip from Hanoi the boat leaves at 09:30 on day three, right after the pass. The boat fare and the shuttle to the dock are included.
The canyon without organising the dock yourself
Your own car down to the water after Ma Pi Leng, a licensed local guide on board, private for your group and tailored on request.
Ha Giang Loop by Private Car — 3 Days3 days, 2 nightsSee the tour →Ha Giang Loop from Hanoi — 4 Days by Private Car4 days, 3 nightsSee the tour →Questions about Tu San canyon
How deep is Tu San canyon?
Its walls are usually given as 700 to 900 m high, and some Vietnamese sources say nearly 1 km. The narrow section is about 1.7 km long.
Is Tu San the deepest canyon in South-East Asia?
It is described that way by Vietnamese official and press sources, and it is certainly the deepest gorge on the Ha Giang Loop. We have not found an international survey that ranks it.
How do you get into Tu San canyon?
By motor boat from the dock by the Nho Que 1 dam, which runs from 07:00 to 18:30. The fare includes a shuttle from the car park to the water.
How long is the Tu San canyon boat trip?
About 45 to 60 minutes on the water, into the narrow section and back. Allow one and a half to two hours including the shuttle.
Can you see Tu San canyon without taking the boat?
Yes. The lay-bys on Ma Pi Leng Pass look straight down into it, and the Sky Path above the road has a pavilion looking down into it.
What is the best time of day for Tu San canyon?
Early morning or after about 15:00, when low light shows the texture of the walls and the water looks greener than it does under the midday sun.
Tu San from the water, by private car
Car, driver, licensed local guide, rooms, meals, the boat into the canyon and the permit in one price for your group, free to cancel until 5 days before.
★Ha Giang Loop by Private Car — 3 DaysThree days around the Ha Giang Loop in your own car, from Ha Giang city — Heaven Gate, Lung Cu, the Sky Path on Ma Pi Leng and a private boat on the Nho Que. · 3 days, 2 nightsfrom$354/ person›
Choose your group size · price is the group totalSolo traveller$975BOOK →2 guests$1,075BOOK →3 guests$1,315BOOK →4 guests$1,415BOOK →See the full tour page →Ha Giang Loop from Hanoi — 4 Days by Private CarDoor to door from Hanoi: four days on the Ha Giang Loop with your own car, a licensed local guide and a good hotel every night. · 4 days, 3 nightsfrom$543/ person›
Choose your group size · price is the group totalSolo traveller$1,515BOOK →2 guests$1,640BOOK →3 guests$2,045BOOK →4 guests$2,170BOOK →See the full tour page →Canyon figures, boat hours and fares were checked in September 2026; published measurements of the gorge vary.