Plastics are the main type of litter in marine environments, but its fate and impacts are still being unraveled. Plastics at sea have both ocean and land-based sources, and although rivers and estuaries are great contributors of land-originated plastics, this kind of pollution is poorly documented in these environments. We investigated the abundance and characteristics of floating litter collected in surface waters of the Patos Lagoon estuary and its adjacent coastal region. Patos Lagoon is one of the largest coastal lagoons in the world, harboring the second largest Brazilian port in its estuarine portion, and being an important fishing site. Litter was collected using a fishing net (9 m x 1.80 m, mesh sizes: 13 mm in the wings and 5 mm in the center) at five stations within the estuary and two stations in the adjacent coast. Sampling was carried out monthly between August 2019 and February 2020. The collected items were counted, weighed and classified according to type, color and probable source (UNEP, 2016). A total of 2,784 items (weighing 4496 g) were collected, with plastic representing 99% of the materials. Most plastics were fragments (78%) and lines (19%). Transparent (51%), white (22%) and blue (17%) were the dominant colors of items. From the total, 311 items were sampled in estuarine waters, while 2,443 were from the coastal region immediately adjacent to the access jetty of the estuary. This suggests that the jetty could act as a barrier accumulating litter at this portion. The dominance of fragments in transparent/white colors suggests the breakdown of larger items in the environment, and the high amounts of nylon lines indicate contamination caused by fishing activities. Monitoring the types and sources of plastics is essential for mitigating its impacts.