Arroyo Isletas is a freshwater stream located in Entre Ríos Province, Argentina, flowing through the region near the city of Gualeguaychú. Situated in one of Argentina's most celebrated fishing provinces, this arroyo winds through the characteristic landscape of Entre Ríos — a province whose very name, meaning "between rivers," speaks to its identity as a land defined by waterways. The stream forms part of the rich network of arroyos, wetlands, and river systems that make this corner of northeastern Argentina a destination for anglers seeking the diverse and hard-fighting freshwater species native to the Río de la Plata basin.