Plastic contamination is an increasing environmental problem. Many aquatic species and birds get entangled, wounded or ingest plastic fragments with devastating effects. Besides is plastic also found to effect plants and even humans. Most of the plastic in the sea originates at land and is transported via the wind, rivers and coasts to the sea. Based on data of the plastic waste production of the inhabitants of the Scheldt basin, the waste production of inland navigation and waste created in the ports, this study modelled the flux of macro plastic from the Scheldt basin towards the sea. This flux is between 7.9 and 48.6 tons a year with the average scenario indicating 18.2 ton. This is a small number compared to major rivers in Europe and could be, besides the fact that the basin is much smaller than the other basins, related to the good waste management with only 0.6% of the yearly plastic waste production which is littered. Using limited data on the cleaned-out materials and by estimating a waste input per kilometre, a second model was made to study the spatial behaviour of the macro plastic distribution in the waterways. While this model could not be correct calibrated, an indicative calibration using the modelled flux showed that the Maritime Scheldt delivers double the amount of plastic compared to the ‘kanaal Gent-Terneuzen’. The large cities are the major contributors of plastic litter within the basin. To reduce the flux of macro plastic towards the sea, it is important to reduce the amount of plastic waste generated and to improve the management of plastic waste further. Also, additional research is necessary to determine the plastic waste hotspots and to test the effect of different measurers to reduce plastic waste.