The Riachuelo, formally known as the Matanza-Riachuelo River, runs through the southern part of Buenos Aires before emptying into the Río de la Plata. The river has long been considered one of the most polluted waterways in Latin America, carrying a legacy of industrial discharge, sewage, and toxic waste accumulated over many decades of heavy use as an industrial port corridor. Its basin spans roughly 2,000 square kilometers and is home to approximately ten percent of Argentina's population.

Navigation on the Riachuelo was judicially suspended in 2011 due to severe contamination. That prohibition has since been partially lifted for the section running from the confluence with the Río de la Plata up to the Nicolás Avellaneda Bridge, near the Rocha Bend. This is currently the only stretch where navigation is permitted for tourism purposes. Organized boat tours operate on this section, with at least one company, Sturla, offering guided river navigation experiences.

Despite the partial reopening, water quality remains a serious concern. Cleanup efforts backed by the Argentine government and the World Bank have made measurable progress — including a major sewage infrastructure project involving more than 40 kilometers of tunnels — but authorities have acknowledged that full environmental remediation will take many more years. Officials have drawn comparisons to the Thames and the Seine, noting that even decades of investment in those rivers has not produced swimmable water quality. Paddlers should treat contact with the water as a significant health risk.

The navigable section passes through historically and culturally significant urban scenery, including industrial-era architecture and the iconic waterfront areas of the southern city. There are no paddler-specific facilities, dedicated launch points, or seasonal water temperature data for independent paddling use. Given the ongoing pollution, restricted navigation zones, and the absence of established paddling infrastructure, the Riachuelo is not a practical destination for independent recreational paddling at this time.