When an accident involving oil spill occurs, forecasting the behaviour of the oil slick and understanding in advance where and when it will reach the coastline is crucial to organize an efficient emergency response while limiting severe environmental and economic consequences. After the Wakashio oil spill accident at Mauritius, CMCC Foundation, cmcc srl, in collaboration with Mercator Ocean International, deliver a bulletin modelling and forecasting the oil spill trajectory in the period of interest.