Cigarette butts are the most common type of litter found in beaches worldwide: in the 2018 World Cleanup Day, Ocean Conservancy counted 5.7 million cigarette butts collected from beaches from 122 countries. Over 20 thousand of these butts were from the Brazilian coast, where they also represented the most abundant item. Cassino beach is an extensive sandy beach located in south Brazil, and has intense portuary, fishery and touristic activities. Beach use, especially tourism, is seasonal and concentrated near the urban area of the Cassino neighborhood. This study aimed to map the spatial and seasonal patterns of the amounts of cigarette butt at Cassino beach. During 27 months (between 2016 and 2019), through 200m2 transects (in triplicate) of the sand strip, we collected a total of 4,002 cigarette butts, representing 14.7% of total items. There was a direct relationship between human activities and the number of cigarette butts. During the austral summer, when beach use increases, the number of cigarette butts also increases: 2,709 were found in summer, compared with 80 in the winter. We also observed a higher concentration of cigarette butts at the dune base (7.80 items.100m2) than at the wrack line (1.70 items.100m2). Cigarette butts are an indicator of how beach activities are related to beach pollution, and they had a higher frequency in sites with more beach users when compared to areas with lower urban occupation. Discarded cigarette butts contain plastic filters and numerous toxic chemicals that can affect environmental and human health. To solve this problem, it is important to develop science-based public policies, with management actions focused on environmental education activities and an increase in the number of receptacles for the proper disposal of cigarette butts.