Marine debris is one of the environmental problems highlighted in this decade. These pollutants are present in various environments worldwide, ranging from highly urbanized beaches to even the most remote islands. This study aimed to understand the factors involved in the origin and distribution of solid waste and microplastics via their characterization and quantification on beaches of three islands in southeastern Brazil: Trindade Island/ES, Grande Island/RJ, and Paquetá Island/RJ. These islands vary in their proximity to the continent and exhibit distinct patterns of occupation and use. Sediments were collected at three points in wet and dry sand on each beach and then analyzed and quantified. The results showed that the highest density of solid waste was 0.27 items.m ^-2 on Trindade Island, followed by Paquetá Island/RJ, with 0.10 items.m ^-2 , and Grande Island/RJ, with 0.07 items.m ^-2 . Plastic was the most abundant material on the three islands studied. The highest concentration of microplastics was found on Paquetá Island (21.98 items.kg ^-1 ), followed by Grande Island (8.85 items.kg ^-1 ) and Trindade Island (2.44 items.kg ^-1 ). The blue color and fragments were prevalent on the three islands, accounting for 31 and 74% on Trindade Island, 44 and 77% on Grande Island, and 31 and 68% on Paquetá Island, respectively. Microplastics smaller than 1,000 μm predominated on Trindade Island (76%) and Grande Island (68%), whereas, on Paquetá Island, microplastics with sizes ranging from 1,000 to 5,000 μm prevailed (62%). This research demonstrated that the abundance and distribution of solid waste and microplastics are determined by several factors, including oceanographic processes and anthropic influence, resulting from the different forms of use and occupation of the islands studied.