To improve the information on the state of the Indonesian marine environment that is gained from satellite data, the joint German-Indonesian Pilot Study Indo NACE (Indonesian seas Numerical Assessment of the Coastal Environment) aims at producing oil pollution density maps in Indonesian waters. One of the case study areas is Seribu Islands, located in the northern part of Jakarta Bay in the western Java Sea. Seribu Islands is part of several Marine Protected Areas (MPAs) that are vulnerable to oil pollution, since close to those MPAs a number of offshore oil platforms are located. Based on these conditions, and in order to trace both potential oil pollution sources and potential impacts on the environment, the assessment will be based on in-situ measurements and numerical models. This region is strongly influenced by the monsoon, with ocean currents generally flowing from north towards east during the west (winter) monsoon, and flowing westward during the east (summer) monsoon.