The book Floating Marine Debris along Indonesian Coasts. An Atlas of Strandings based on Lagrangian Modelling was conceived within the framework of a collaborative research project conducted jointly by the Indonesian Ministry of Marine Affairs and Fisheries (KKP), Collecte Localisation Satellite (CLS), and the French National Research Institute for Sustainable Development (IRD), and funded, since early 2020, by the Agence Française de Développement (AFD). The project aims to sustain the monitoring and modelling of marine debris in the Indonesian seas and beyond. The final goal is to strengthen Indonesian agencies in their efforts to rise public awareness about marine pollution by plastics, and to implement adapted mitigation strategies. Due to their high durability and relatively low-cost production, plastics constitute by far the predominant fraction of solid waste products, a substantial proportion of which is eventually discharged into the oceans. Emissions and circulation of plastic and marine debris follow complex pathways that vary locally according to waste management, population density and hydrology, but the majority of litter runs off from rivers. A major priority is to understand the sources of floating plastic debris and their eventual beaching locations and to identify potential connectivity patterns at the regional and basin ocean scales. A Lagrangian assessment of the debris dispersion originating from 21 major rivers in Indonesia was carried out as a means to identify the concentration at sea, as well as the geographic and temporal distribution of stranding along Indonesian coastlines based on a state-of-art ocean modelling. The present atlas detailing the results of this assessment at the regional scales should be viewed as a first effort to establish the river connectivity implied in the marine dispersion of surface plastic debris in Indonesia.