Rio Paraibuna is a river flowing through the state of São Paulo in southeastern Brazil, serving as a tributary of the larger Paraíba do Sul river system. The river originates in the highlands of São Paulo state and winds through a region of significant ecological importance, eventually meeting the Paraíba do Sul near the coordinates of 23°22′06″S, 45°39′50″W. The watershed is characterized by the lush Atlantic Forest biome typical of southeastern Brazil, with riparian vegetation lining much of its course. The river draws anglers from the surrounding region and supports a diverse community of native and introduced fish species, making it a productive destination for freshwater fishing in the Vale do Paraíba region.