The Rio Guajú is a river in Northeastern Brazil, forming part of the border between the states of Paraíba and Rio Grande do Norte. Its mouth, known as the Foz do Rio Guaju, is located near the town of Baía Formosa in Rio Grande do Norte. This area is a noted point of interest for visitors. The river's estuary provides a scenic environment where the river meets the ocean, and guided tours are available in this area. One local guide operating there is known by the nickname "caranguejo." The overall character of the experience at the river mouth is described as a beautiful walk, suggesting a calm and accessible shoreline suitable for exploration. The river's geographical coordinates are approximately 6°29′16′′S.