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The wide, brown Mekong seen from Mount Phousi in Luang Prabang, between wooded hills and mountains

Photo by Frank Eiffert on Unsplash

The Mekong, from source to delta

Close to 5,000 kilometers from the glaciers of the Tibetan Plateau to the South China Sea. What the river crosses, what it feeds, what threatens it: the Mekong explained before you travel it.

By Pierre-Marie Coupry · updated · sources

The Mekong from end to end

You can't travel the Mekong from one end to the other. Its first half runs through China, in gorges few travelers follow. The trip really starts at the Golden Triangle, where the river becomes a border: it crosses Laos, runs along Thailand, hits the Khone Falls, widens in Cambodia, then splits into the Vietnamese delta.

This line is our reference across the site: every stop has its place on it, from upstream to downstream.

China China Lancang Myanmar · Laos (border) Thailand · Laos (border) Laos Laos Thailand · Laos (border) Thailand · Laos border Laos Laos Cambodia Cambodia Vietnam Vietnam delta Source km 0 Jinghong km 2,220 Golden Triangle km 2,540 Luang Prabang km 2,890 Vientiane km 3,340 Pakse Khone km 4,190 Phnom Penh km 4,590 South China Sea km 4,909 ← upstream downstream →
  1. Source km 0 · China
  2. Jinghong km 2,220 · China
  3. Golden Triangle km 2,540 · Myanmar · Laos (border)
  4. Luang Prabang km 2,890 · Laos
  5. Vientiane km 3,340 · Thailand · Laos (border)
  6. Pakse Laos
  7. Khone Falls km 4,190 · Laos
  8. Phnom Penh km 4,590 · Cambodia
  9. South China Sea km 4,909 · Vietnam
Kilometers from the source: total length minus the distance to the sea, measured along the Natural Earth course and checked against Mekong River Commission station chainage; rounded to the nearest 10. Total length: 4,909 km (Liu et al., 2009); the Mekong River Commission uses 4,350 km. In blue, underlined with dots: the river is a border.

The Mekong: one river, six countries

Each country has its own Mekong. In China, gorges; in Laos, a road; in Thailand, a border; in Cambodia, a river-lake that fills the Tonle Sap; in Vietnam, a maze of canals.

  • China

    The Lancang

    Nearly half the river, from its source on the Tibetan Plateau to the gorges of Yunnan. A cascade of dams since 1995.

    The source and the Mekong in China →

  • Myanmar

    The Golden Triangle

    The river separates Myanmar from Laos for a few hundred kilometers, down to the Golden Triangle. Few roads, hardly any travelers.

    Not in our guide for now.

  • Laos

    The heart of the trip

    Slow boat, Luang Prabang, Vientiane, the 4,000 Islands. The river crosses the country, then runs along it.

    The Mekong in Laos →

  • Thailand

    The right bank

    The Mekong forms the border with Laos for hundreds of kilometers, from Chiang Khong to Khong Chiam.

    The Mekong in Thailand →

  • Cambodia

    The wide river

    The dolphins of Kratie, Phnom Penh and the Tonle Sap River.

    The Mekong in Cambodia →

  • Vietnam

    The delta

    The river's branches, the canals and the markets of Cần Thơ, all the way to the sea.

    The Mekong in Vietnam →
CHINAMYANMARLAOSTHAILANDCAMBODIAVIETNAMSouthChina SeaSourceJinghongLuang PrabangPhnom PenhNatural Earth
The Mekong River map and the countries it flows through →

What the Mekong hides

One of the richest rivers in the world for fish, and one of the most dammed. Six numbers to understand what's at stake.

  • 300 kg

    The giant stingray of Stung Treng

    In June 2022, a 4-meter freshwater stingray, caught then released in Cambodia: the largest freshwater fish ever measured.

    Mongabay, June 2022

  • 293 kg

    The giant catfish

    The former record, caught in Thailand in 2005. Its population is estimated to have fallen by about 80% over recent decades.

    IUCN, via AP, December 2024

    The Mekong giant catfish →

  • 118 dolphins

    The Irrawaddy dolphins

    According to Cambodia's official count of April 27, 2026, in the river's deep pools between Kratie and the Khone Falls. Six births since the start of the year.

    Phnom Penh Post, April 2026

    The Mekong's dolphins →

  • 12 dams

    A dammed river

    In operation on the Chinese stretch, plus two in Laos since 2019 (Xayaburi, Don Sahong). Less sediment, fewer fish downstream.

    Mekong River Commission, 2026

    Mekong River dams →

  • 5,224 m

    The source

    On the Tibetan Plateau, in Qinghai province. Its exact location, and so the river's length, is still debated.

    Liu et al. (2009)

    Mekong River length and source →

  • 2 directions

    The river that reverses

    In the rainy season, the Mekong swells and pushes the Tonle Sap River back toward the lake, which grows to several times its size. It flows normally again when the rains end.

    Mekong River Commission

    The Tonle Sap reverses its flow →

The Mekong: your questions

What we get asked most often, and a few misconceptions.

Can you travel the whole Mekong by boat?
No. The Khone Falls, on the border between Laos and Cambodia, cut off navigation. No boat links China to the sea.
Is the Mekong the longest river in Southeast Asia?
Yes. At 4,909 km by the measurement we use, it's the longest in Southeast Asia and the 12th longest in the world. Published figures range from 4,350 to 4,909 km: not everyone measures from the same source, or to the same mouth of the delta.
Why is the water brown?
Because of the silt it strips from the mountains of Yunnan and Laos and carries down to the delta. Before the first dam, in 1990, the river carried about 160 million tonnes of sediment a year. Reservoirs now trap much of it: the load is thought to have dropped to around 80 million tonnes, according to a Mekong River Commission report cited by Viet Nam News.

Sources: Liu et al. (2009) and Mekong River Commission (length); Britannica and Wikipedia (ranking); Mekong River Commission via Viet Nam News (sediment); Mekong River Commission (Tonle Sap); Mongabay (giant stingray, 2022); Mekong River Commission (dams, 2026); IUCN via AP (giant catfish, 2024); Phnom Penh Post and WWF Cambodia (dolphins, 2026); Natural Earth outlines.

Traveling the Mekong

Once you have the river in mind, three questions remain: when to go, which way, and whether to take a cruise.