The Truckee River flows out of Lake Tahoe through Tahoe City, and in summer it is one of the most popular float trips in the Sierra Nevada. The stretch from Tahoe City to the River Ranch Lodge — about five miles of easy Class I–II water — takes two to three hours by raft and is gentle enough for families with young children.
Several outfitters in Tahoe City rent rafts, tubes, and kayaks, typically with shuttle service back to town at the end. The trip is more about floating and scenery than whitewater excitement: the river is lined with pines and willows, the water is cold and clear, and the summer crowds are part of the experience rather than a reason to avoid it. Weekday mornings in July and August are the best time — enough people to be social, not so many you feel like you're in a theme park.
Temperatures in the Truckee drop sharply after Labor Day; the water remains cold throughout summer even when air temperatures are high. Wetsuits are available from rental operators if you plan to spend time in the water rather than just on it.