The Integrated Monitoring and Assessment Programme (IMAP) aims to quantitatively assess the status of the Mediterranean Sea and coast in an integrated way. There are 27 indicators that are linked to one of 11 Ecological Objectives. Candidate Common Indicator 25 “Land cover change” (CCI25) has focused on urbanisation – a process that highly compromises ecosystem integrity and is irreversible. CCI25 calculates shares of five land cover classes for the coastal zone of 10 km width. Additional parameters calculate areas under protection and areas up to 5 m above sea level. Aher the initial calculation, the calculation is repeated every 6 years and changes are detected. The CCI25 is demanding in terms of data: it requires homogeneous data of the entire Mediterranean; certain spatial and temporal resolution; and fitting the semantics of the indicator. National data cannot meet these needs, so the use of global open maps has been tested. This paper presents results for key data sets: land cover, elevation and coastline. The coastline from OpenStreetMap fully meets the needs as well as the Copernicus DEM 30 global surface model. Regarding land cover data, the ESA WorldCover Project has been revealed as the most promising one.