Estero Las Cadenas is a wetland waterway located in the O'Higgins Region of Chile, approximately 80 kilometers south of Santiago. The estero flows through predominantly agricultural land in a sparsely populated area, with a population density of around 23 inhabitants per square kilometer. It is associated with two municipalities: San José de Marchigüe and Pichidegua, and its coordinates place it at approximately 34°11′S, 70°50′W.

The waterway is notable for its position within a wetland ecosystem that supports diverse local flora and fauna. A key geographical feature is that the estero leads to the confluence of the río Cachapoal and the río Tinguiririca, the point where Lago Rapel originates. This confluence serves as the primary destination for guided paddling tours operating in the area.

The standard guided route covers approximately 5 kilometers. Morning departures, which typically last around three hours, allow paddlers to reach the river confluence, while afternoon or sunset departures run approximately two hours. Both kayak and stand-up paddleboard (SUP) options are available. The operator Cachapoal Salvaje, registered with Sernatur, runs guided tours on this route and has also offered specialty experiences such as nighttime astro-kayak sessions with stargazing from the water.

Facilities at the launch point include restrooms, changing rooms, secure parking, a picnic area, and a first aid kit. Guides hold certifications in remote area rescue, kayak rescue, and CPR. The meeting point location is provided to participants upon booking.

Tours have been offered on weekday evenings and weekend mornings and afternoons, suggesting the waterway is accessible across multiple times of day. The wetland environment provides an opportunity to observe local biodiversity, and a quick-reference biodiversity identification guide for the wetlands of Pichidegua — covering Humedal Las Juntas and Estero Cadenas — has been produced in association with Cachapoal Salvaje, indicating the area holds recognized ecological value.