Río Puelo originates in Argentina near Cerro Tronador and flows westward through the Los Lagos Region, draining through a glacial valley before emptying into the Reloncaví Estuary on the Pacific coast. The river passes through Lago Tagua Tagua along its course, and its waters are notably turquoise and clear. The surrounding landscape consists of temperate rainforest, mountains, and wetlands, with Parque Nacional Pumalin bordering the river on the left bank in its lower reaches.

The river offers a wide range of paddling character across its length. The upper section entering Chile from Argentina begins as Class II water, then within roughly six kilometers is compressed into a narrow, technically demanding Class IV-V canyon. Approximately six more kilometers downstream lies a second canyon known as El Portón, rated Class III-IV. Below El Portón, the river transitions to Class II-III minus conditions through lakes and flatwater sections, eventually becoming navigable by sea kayak all the way to the ocean. The full traverse from Argentina to the Pacific represents a complete water crossing of the Andes.

Access to the valley improved significantly about ten years ago when a road was constructed into the lower Puelo Valley, which had previously been more easily reached from the Argentine side via lake crossings. From Puerto Varas, the river can be reached via Route 225 to Ensenada, then Route V-59 to Puelo. Alternatively, travelers can take the Carretera Austral to Caleta La Arena, cross by ferry to Caleta Puelche, and continue on Route V-69 to Puelo. Bus service from Puerto Montt terminal runs approximately four times daily.

The climate is rainy and temperate year-round, with precipitation occurring in all seasons. Sport fishing for rainbow trout, marrón, and fario is available, with the fishing season running from September to May. The river corridor supports diverse birdlife, and the wetland sections are particularly noted for bird variety. Guided kayak trips on the calmer sections, including paddles on Lago Tagua Tagua, are offered by local operators and are rated as easy to moderate, suitable for groups of two to eight people and open to participants over eleven years of age.