Si Phan Don (4,000 Islands)

A group of Mekong islands in Champasak Province, southern Laos, near the Cambodian border. Don Khong is the largest island, and Don Det and Don Khon are the main traveller bases. Khone Phapheng, nearby on the mainland, is the largest waterfall by volume in Southeast Asia. Laos' first railway, a French portage line, was built across Don Khon and Don Det, starting in 1893. Since February 2022, Irrawaddy dolphins are considered functionally extinct on the Lao side of the border.

Si Phan Don, meaning 'four thousand islands', is a group of islands in the Mekong River in Champasak Province, southern Laos, along the Cambodian border. The river breaks into many channels around the islands, and roughly half of them are underwater when the Mekong floods. Don Khong is the largest island. Don Khong, Don Det and Don Khon get most of the visitors, and the smaller islands are largely uninhabited.

Life on the islands is built around farming and the river. Tourism Laos describes largely self-sufficient villages that grow rice, coconuts, sugar cane and vegetables and weave their own textiles. Don Det is the more laid-back island, with guesthouses, bars and restaurants. Don Khon holds most of the colonial railway remains and the path to the Li Phi falls. Walking trails connect villages and viewpoints on both islands.

The islands sit among waterfalls and rapids that make this stretch of the Mekong impossible to navigate. Tourism Laos describes Khone Phapheng, on the mainland east of Don Khon, as the largest waterfall by volume in Southeast Asia. Its highest drops reach about 21 metres, and its rapids run for close to 10 km. On Don Khon, Tad Somphamit is part of the wider Li Phi falls, a stretch of falls and rapids about 20 km long.

When to go: Water levels change a great deal through the year. At high water roughly half of the islands are submerged and the falls carry far more water, while lower water exposes more of the islands and channels. Check river conditions locally before planning boat trips or waterfall visits.

Getting there: Si Phan Don is about 150 km south of Pakse along Route 13 South, near the Cambodian border. Khone Phapheng is on the mainland, about 13 km from the border, east of Don Khon and about 6 km south of Don Det. The islands are reached by boat from the mainland, and the old French railway bridge connects Don Det and Don Khon.

In 1893 the French colonial administration opened a narrow-gauge portage railway on Don Khon. It let dismantled river boats, freight and passengers get around the Khone falls and continue up the Mekong. In the 1910s the line was extended 3 km across a 170-metre concrete viaduct to Don Det, for a total of about 7 km of track. The last train is reported to have run in 1940.

The viaduct still links Don Det and Don Khon, although the rails have been removed. A rusty steam locomotive built in 1911 by Orenstein & Koppel stands under a protective shed at Ban Khon on Don Khon. It is the only steam locomotive still existing in Laos.

The deep pool below the falls, on the border with Cambodia, was long known for Irrawaddy dolphins. That subpopulation fell from 17 animals in 1993 to one male, which died in February 2022 after getting caught in fishing gear. WWF said the death most likely meant the species was extinct in Laos. The remaining Mekong population, estimated at about 89 animals, lives in a roughly 180 km stretch of the river inside Cambodia.

Tourism Laos says Tad Somphamit takes its name from a sacred Buddha image that King Fa Ngum dropped into the water. It also notes that the name Li Phi properly refers to the whole stretch of falls and rapids, not only Tad Somphamit.

1. Tourism Laos · Champasak Province ↗
2. Tourism Laos · Waterfalls - Khone Phapheng Falls ↗
3. Mongabay · Death of last river dolphin in Laos rings alarm bells for Mekong population ↗
4. Wikipedia · Si Phan Don ↗
5. Wikipedia · Don Det-Don Khon narrow gauge railway ↗