In the frame of the German-Indonesian pilot study IndoNACE (Indonesian Seas Numerical Assessment of the Coastal Environment), a wealth of SAR data of two dedicated regions in Indonesian waters are being analysed with respect to the imaging of marine oil pollution. Numerical tracer studies using a regional 3-d numerical model are used to aid those analyses and to help understanding the observed seasonal variations in marine oil pollution. Our first results are based on 130 ENVISAT ASAR images of each of the two regions of interest, the 'Western Java Sea' and the 'Makassar Strait' and indicate that most pollution was found in areas of high ship traffic and of intense oil production.