Praia da Boca do Rio Beach owes its name to its natural configuration of river mouth, functioning as the mouth of three streams that flow here: Ribeira de Vale Barão, Ribeira de Vale de Boi and Ribeira de Budens. The convergence of these water lines developed a wetland near the mouth, known as “Paul da Lontreira” because it constitutes a habitat for otters that also frequent the marine area, a very rare habit in these mammals that tend to explore riverside areas. The entire surroundings of Praia da Boca do Rio are rich in biodiversity, especially the avifauna. Its fishing vocation dates back, at least, to the Roman period. The building that dominates the cove dates back to the 18th century, having been built by order of the Marquis of Pombal to serve the fishermen of the tuna fishing trap that operated there. In the interior marsh, geological research detected levels of sedimentary deposits generated by the Great Earthquake of 1755. It invites you to walk in the surroundings and provides an interpretive guide available in this application. With marked Mediterranean characteristics, this beach is part of the Southwest Alentejo and Costa Vicentina Natural Park.