The NSW marine debris threat and risk assessment identified microplastics as a priority threat to the environmental and socio-economic values of the marine estate. However, there are significant knowledge gaps regarding microplastic distribution and abundance and the nature of the threat which they pose. This study assessed microplastic abundance in over 50 estuaries along the NSW coastline to create a reference database. Over the 2021/2022 La Nina summer, repeated, replicate surface water samples were collected in the estuaries using a neuston net (mesh size 0.333mm). The microplastics net was towed 15 meters behind a boat/canoe for a period of five minutes each tow. Over 200 samples were analysed and reported as the number of microplastics per kilolitre (m3) of water in each of the estuaries. This large-scale study; 1. Highlighted the NSW estuaries with the highest microplastic concentration; 2. Identified priority estuaries in which to focus finer scaler research into microplastic sources; 3. Created a baseline dataset that can be used for ongoing monitoring measuring the success of strategic management actions aimed at reducing microplastic pollution.