By the time the Mekong reaches Champasak, it has picked up more than 95% of its flow from upriver tributaries. During the monsoon season months of August and September, the volume of water moved by the Mekong increases more than 10-fold from its March and April flow rates.
The Mekong widens before the 4,000 Islands, where the river appears to take the shape of a 15-km wide delta, as channels of raging rapids break up the single waterway. These rocky flumes come together at Khone Pha Pheng, Southeast Asia’s largest waterfall by volume with a drop of 21 metres. The Mekong continues for about 13 km to Cambodia.
These falls and rapids prevent boats from sailing upriver, though the French colonials used their ingenuity to bypass the turbulent waters and continue upstream. However, Mekong villages view the Khone falls area as prime angling areas as they can easily trap the fish swept up in the raging waters.
Pakse, the Champasak provincial capital, is the first major port as the river flows through the Lower Mekong. The city sits at the Mekong’s convergence with the Xe Don River, which is about 245 km downriver from Savannakhet, 135 km by road from Ubon Ratchathani, Thailand, and some 150 km from the Cambodian border.
The Pakse landing just north of town offers private long boats for the 40-km cruise to Ban Phapin, 2 km north of Champasak Town and the Vat Phou UNESCO World Heritage Landscape. Ferries also head to Champasak Town from a landing near Route 13 (Km 30). Boats from Ban Phapin head to Don Daeng, which offers accommodation and cycling circuits that stop at temples, an ancient forest stupa, and basket weaving village. The upscale “Vat Phou” cruise vessel offers a 3-day program that departs from Pakse, with stops at Champasak and further downriver to the 4,000 Islands.
The Mekong widens considerably after passing Vat Phou and Don Daeng, and begins forming the 4,000 Islands, reaching Don Khong after a 100-km run that trims the Xe Pian National Protected Area. Khong Town, the one-time French colonial headquarters in Champasak Province, can be accessed from Route 13 at Hat Xay Khun by bridge or ferry. A paved road with old colonial bridges encircles the island, with stops at ancient Buddhist temples and religious shrines, a Mekong Riverside village, Khmer ruins, and a village producing palm sugar. Khong Town presents the District Museum in a French colonial structure that once housed the provincial governor, and a row of clean guesthouses.
Don Khone and Don Det are located14 km south of Don Khong and accessed by ferry from Route 13’s Nakasan visitor center to piers on both islands' upriver shores. At this point, rapids and falls block navigation on the Mekong, while presenting natural and cultural attractions such as Li Phi Waterfalls and Pa Soy Village, where bamboo fish traps are built across the rapids. The islands’ highlight is the French colonial infrastructure built to bypass the obstructive rapids, including remnants of piers, steam locomotives, the 7-km railway route, and a railroad bridge to Don Det and its gantry.
The Nakasan visitor centre offers longboat tours from Hang Khone Pier to see the rare freshwater Irrawaddy dolphins, investigate the maze of downriver channels, and visit villages with homestays. Ban Khone offers clean, simple guesthouses while Don Det features more upscale rooms. Some sites can be reached by foot or the island’s tram, while rented bicycles and scooters open access to all attractions. A short drive south of Nakasan and near Cambodian border checkpoint is Southeast Asia’s largest waterfall by volume, Khone Pha Pheng, a long way from the river’s Lao start in The Upper Mekong.