Technically, you can swim in the Amazon River, but it is not generally recommended without expert local guidance. While the river is famous for piranhas and anacondas, these creatures rarely attack humans unless provoked or during times of extreme food scarcity. The real dangers are often invisible: strong currents, submerged debris, and parasites like the candiru (which urban legends claim can enter human orifices, though scientific evidence is slim). Bacterial infections from pollution or parasites are a much more common risk than a shark or caiman attack. However, many 2026 eco-tours include a "swimming stop" in specific blackwater areas (like the Rio Negro), where the high acidity naturally keeps most predators and bacteria at bay. If you choose to swim, the safest way is to stay in the middle of the river off a boat rather than near the muddy banks, as creatures like stingrays and caimans are more likely to be lurking in the shallow, shoreline waters.