Peracarids (Crustacea: Peracarida) are an important component of soft-sediment faunas and are considered good indicators of quality of water and sediments. Nevertheless, little is known about diversity of peracarid crustaceans on the shallow subtidal sediments of Playa América, a sandy beach in the Ensenada de Baiona (Galicia, NW Spain). Therefore, the peracarid fauna of its shallow subtidal zone was studied in a fine-sand site at 4-m depth from February 1996 to February 1997. Monthly sampling yielded a total of 4753 individuals belonging to 60 species. Amphipods were dominant in number of individuals and species followed by cumaceans. The assemblage showed a stable composition in species through the year and was numerically dominated by a few species, namely the amphipods Siphonoecetes kroyeranus and Microprotopus maculatus and the cumacean Pseudocuma longicorne. These species showed large monthly fluctuations in abundance, with maximal values between summer and autumn.