The marine debris ingested by megafauna species (Trichiurus lepturus, Chelonia mydas, Pontoporia blainvillei, and Sotalia guianensis) was recorded in a coastal area of southeastern Brazil (21-23°S). Marine debris was recorded in all species, mainly consisting of plastic material (flexible and hard plastics - clear, white, and colored- and nylon filaments). The 'pelagic predators' T. lepturus and S. guianesis showed the lowest percent frequencies of debris ingestion (0.7% and 1.3%, respectively), followed by the 'benthic predator' P. blainvillei (15.7%) and the 'benthic herbivorous C. mydas (59.2%). The debris found in C. mydas stomachs was opportunistically ingested during feeding activities on local macroalgal banks. In the study area, the benthic environment accumulates more anthropogenic debris than the pelagic environment, and benthic/demersal feeders are more susceptible to encounters and ingestion. The sub-lethal effects observed in C. mydas, such as intestinal obstruction due to hardened fecal material, should be considered a local conservation concern.