The Rio Mamoré in Rondônia, Brazil is a major river in the Amazon basin, forming part of the international border with Bolivia near the town of Guajará-Mirim. A primary access point for paddlers is Guajará-Mirim, where a boat crossing to Bolivia operates, taking approximately 15 minutes. The river serves as a significant transportation corridor, with multi-day cargo boat journeys, such as a five-day trip from Trinidad, Bolivia, to Guayaramerín, Bolivia, which is directly across from the Brazilian town, indicating the river's substantial length and navigability for extended expeditions. The river's ecological significance is highlighted by its diverse aquatic life, including recently described species of catfish from the Panaqolus genus found in the Mamoré and Madeira river systems. The overall character is that of a working tropical river, vital for regional transport and border crossing. The surrounding area is part of the Bolivian Amazon region, suggesting a landscape of rainforest.