The East Fork Big Lost River in Idaho offers an exciting whitewater experience for kayakers and rafters alike. The ideal streamflow range for this river is between 200-500 cubic feet per second (cfs) during the summer months. The river is classified as a Class III-IV, making it suitable for intermediate to advanced paddlers. The segment mileage for the river run is approximately 9.5 miles, with a put-in at the East Fork Bridge and a take-out at the confluence with the Big Lost River.

Some of the notable rapids and obstacles on the East Fork Big Lost River include The Slide, a Class IV rapid with a steep drop and a tight left turn; The Hole, a Class III rapid with a large hydraulic that can be tricky to navigate; and The Squeeze, a narrow section of the river with a rock formation that creates a challenging maneuver for paddlers.

There are specific regulations to be aware of when paddling on the East Fork Big Lost River. The area is managed by the Bureau of Land Management, and a permit is required for overnight camping. Additionally, boaters are required to carry a personal flotation device (PFD) and a whistle, and motorized watercraft are not allowed on the river.