The presence of microplastics in the marine environment has been documented globally, not only in coastal areas but also in the deep sea and the polar regions. However the exact status of microplastic pollution remains widely unknown . Previous studies have attempted to summarize the global distribution of microplastics in the world ocean through numerical modelling . These models, however, have excluded sediment microplastics due to the lack of available data, limiting the possibility of a comprehensive representation of the status of microplastics pollution in the world ocean. Here, we provide for the first time a comprehensive dataset on microplastic pollution in coastal surface waters and sediments of Japan, using established protocols and methods that allows the comparison of surface water and sediment plastic pollution. The data showed and confirmed the ubiquity of microplastics in coastal areas, and the potential role of sediment as a sink for microplastics. Sources and pathways were investigated showing the importance of both environmental and socioeconomic factors in driving microplastic concentrations in coastal areas.