The aim of this work is to identify the value of Spatial Data Infrastructures (SDI) for the coastal resource use and specifically for Integrated Coastal Zone Management (ICZM) in Turkey. For this purpose, some coastal applications with spatial data content have been examined. The concentration in this examination was on the data components and their corresponding providers. The overall aim was to generally evaluate whether SDI could be of any help for the problems encountered in these applications. This evaluation has indicated a great potential for SDI. Following this. one of the coastal applications was examined in more detail. This was the site selection for marine aquaculture and therefore Bodrum, one of the most touristic places in Turkey, was chosen as the case study of this work. The case stud), has also indicated a great value for SDI. Namely, the difficulty experienced both technically and legally in collecting the data for the case study was itself sufficient to appreciate the value of SDIs including Marine SDI. While attainable in seconds via SDIs, it took more than a month to collect the data. Consequently, SDI has been found very valuable for ICZM. It has also been found that SDI would also help for the "lack of employing science" problem in Turkey, and for the incorporation of science into the ICZM programs in general.