Inappropriate disposal, management, treatment of litter are the main sources of plastic accumulation. People, animals, wind, storms, and currents spread continuously the plastic in different sites in the world. Diverse animal groups have been ingesting small particles of plastic, the microplastics (MPs), resulting in negative effects in behaviour, consumption, and nutritional rates. Here, we reported the ingestion of MP by two benthic groups, Ascidiacea and Amphipoda from sites around llha Grande Bay, a Natural Heritage of Humanity site in the Southwest of Brazil.