After a midday hotel pickup by minivan in San Martin de los Andes, travel with your guide on a scenic drive northwest of the city, with a break along the way to purchase coffee and snacks.

Catch sight of Lanín Volcano, cone-shaped and ice-covered, straddling the border of Argentina and Chile, and admire the views of the Andean forests and the Patagonian Steppe.

Get off the bus and stop to take photos of Huechulafquen Lake, a glacial lake and the largest body of water in Lanín National Park. Learn more about the local geology and the eastern end of the lake, which is a well-known fly-fishing location for trout, and also is the mouth of Río Chimehuín — a site that you'll soon be that you’ll be cruising down aboard a raft.

Travel the short distance to the start point to receive a safety briefing and get fitted with a life jacket, helmet, protective suit and an oar. With everyone on board, and with a little push from your guide, head straight into Río Chimehuín. Your descent lasts a little over 90 minutes. Depending on the time of year, expect a mix of Class II and III rapids, providing an easygoing and exciting adventure for both beginners and more advanced rafters alike.

As you whoosh down the river, pass by its nooks and channels with winsome names such as Fast Sauce, Wolf’s Mouth, Wind Wall, Horseshoe and Widows. If you take the tour in the fall, encounter waves that swell as high as 6 feet (2 meters). In the winter, the water flow runs shallower, allowing for a thrilling, bumpy ride over natural stone steps and rocky mazes. During warmer months, look out for an array of wildlife including deer, boar, vultures, ducks and the bright-blue Martin Pescadors — or, river kingfishers — snapping fish into their beaks. Paddle to a deserted beach for a snack break of coffee and facturas, traditional sweet rolls. Relax here for a while and take in the idyllic scenery before climbing back into your raft.  

Finish your descent down the river and then pull ashore at the exit point, where your minivan awaits. Freshen up with a change of clothing and then relax on the journey back to your hotel.