Río Angachilla is a navigable river extending south of Valdivia, in the Los Ríos region of Chile. It is a tributary of the Río Valdivia and forms part of the Valdivia river basin, flowing alongside other waterways that encircle the city, including the Río Valdivia, Río Cruces, and Río Calle Calle. The river serves as the hydrological backbone of the Santuario de la Naturaleza Humedales de Angachilla, connecting the various wetlands that make up this protected area.

The river's flow varies seasonally, with higher water levels during the winter months due to rainfall. This makes winter and early spring the periods of greatest flow, while summer months tend to see lower water volumes.

Two public launch points provide access to the river: the Muelle público on Camino Angachilla and the Muelle público Las Gaviotas. The meeting point for organized tours is Casa Río Vivo, located at the end of Camino Angachilla. Both kayak and SUP are suitable craft for paddling here. Paddlers are asked to move quietly and maintain a minimum distance of 20 meters from wildlife at all times.

The river passes through wetlands rich in birdlife typical of southern Chile, and the broader sanctuary harbors notable fauna including the huillín (South American river otter), a species considered endangered. The surrounding landscape also contains traces of the 1960 earthquake, visible at certain points along the route.

Guided tours are available through several local operators, including Río Vivo, Desde mi kayak, and Namaste y Perreo. A full-day guided trip runs approximately eight hours on the water, while a longer guided route through the sanctuary requires prior paddling experience and takes roughly five hours on the water. The minimum age for organized tours is six years, with a maximum weight of 110 kg and a maximum hip diameter of 90 cm for cockpit fit. Guided trips include a bilingual (Spanish and English) guide, full kayak equipment, a snack, and a box lunch.

The Corporación Humedales de Angachilla administers the sanctuary and promotes low-impact kayak routes as part of its conservation and public awareness mission.