Sun Koshi River Expedition

Sun Koshi River Expedition – A Premier Whitewater Rafting Adventure in Nepal

Sun Koshi River, ranked as one of the top 10 whitewater rafting rivers in the world, offers an unforgettable multi-day river trip combining big volume rapids, warm water, breathtaking Himalayan scenery, rich cultural interaction, and camping under the stars. This adventure is ideal for intermediate and advanced kayakers and rafters, especially during medium to high water flows.

The name “Sun Koshi” translates to “River of Gold,” possibly referring to the gold occasionally panned from its river gravels or the orange hue of the water during the monsoon season, thick with alluvial silt. Originating near Tibet, the Sun Koshi is joined by the Bhote Koshi River just downstream from Barahabise. Navigate Outdoors’ Sun Koshi expedition begins at Dolalghat, where paddlers navigate some of the most thrilling and challenging rapids, concluding at Chatara near Dharan city.

The journey covers approximately 270 km over 7 days in September’s high water, extending to 8-9 days in October, and 9-10 days from November to December due to lower flows and upstream winds.

Flowing from near Kathmandu to eastern Nepal, the Sun Koshi River carves a vast fertile valley where local communities cultivate maize, rice, wheat, and more. It is one of Nepal’s premier whitewater rafting destinations, frequented by paddlers since the 1970s and 80s. The Sun Koshi watershed is mainly fed by Himalayan glaciers and streams stretching from Ganesh Himal to Kanchenjunga—the world’s third highest peak. This vast watershed gathers strength from tributaries draining the highest mountains on Earth, eventually joining the River Ganges in India before reaching the Bay of Bengal.

As a large volume river, Sun Koshi’s rapids are shaped each year by monsoon debris and rockfalls, which means the river’s challenges vary annually. Most rapids are runnable and thrilling, with notable exceptions such as Harkapur II—a big rapid that can be portaged if desired. Navigate Outdoors emphasizes thorough risk assessment and management; our expert guides continuously evaluate river conditions and communicate openly with clients to ensure safe, enjoyable experiences.

Key rapids include No Exit (Grade 3), Harkapur II (Grade 4+/5), Jaws (Grade 4), Rhino Rock (Grade 4), and Big Dipper (Grade 3-4). Some wire pools on flat water sections between the jungle corridor and Waterfall Beach can cause raft flips, adding to the excitement.

During low flow seasons, the Sun Koshi River is perfect for kayakers seeking to improve their skills and progress toward professional guiding. Navigate Outdoors annually offers guide school and kayaking courses for adventure enthusiasts—contact us at info@navigateoutdoor.com for detailed information and upcoming dates.

For those with extra time and interest, we also offer optional excursions on the lower Tamor River. This smaller-volume river features continuous Class 3-4 rapids, including the challenging “Ashram” rapid, and shares the same take-out point as the Sun Koshi River. The Tamor originates near Kanchenjunga, adding a majestic Himalayan backdrop to your paddling adventure.

Trip Details:

Destination: Nepal

Trip Grade: Challenging, Moderate

Max Elevation: 2m/km (10 ft per mile)

Total Duration: 8 – 12 Days

Best Time: April – May & October – November

This Sun Koshi river expedition perfectly complements popular trekking routes in Nepal, such as the Everest Base Camp trek, Upper Mustang trek, and Annapurna Circuit, offering a well-rounded Himalayan adventure combining river rafting, cultural immersion, and stunning natural beauty.