Calopadia saxicola is described as new to science. The species grows on rocky shores in southern Brazil and is characterized by the corticate thallus, pruinose apothecia with brownish to reddish brown disc, mainly 2–3-spored asci with muriform ascospores, and the absence of secondary metabolites. A description with ecological data, figures, comments and a key to all species in the genus known from Brazil are given.