Pollution caused by marine oil spills can lead to persistent ecological disasters and severe social and economic damages. Numerical simulations are useful and essential tools for accurate decision making during emergencies and planning response actions. In this study, we applied the Princeton Ocean Model (POM) to determine current data, including seawater velocity, salinity, and temperature, and we obtained the fate and trajectory of spilled oil using OpenOil. Several probable oil slicks around Taiwan were simulated over time (12 months) and space (four spill locations in the marine area of each coastal city or county) using the model. The percentage risk under the effect of an oil spill is estimated. The risk zone of the coastal waters of Taiwan was identified based on the frequency of simulated oil slicks hitting the coast and sensitive resources. This information not only helps authorities guide the preparation of effective plans to minimise the impacts of oil spill incidents but could also be used to improve regulations related to shipping and vessel navigation in regional seas.