The targeted area in Greece is the Protected Area of northern Karpathos and Saria (GR4210003). According to the standard form of the SCI, its marine part has an area of 5181.74 ha, i.e. about 45% of its total area, which includes habitat 1110, habitat 1120, habitat 1170 and habitat A5.531.Bottom substrates were surveyed with a DeepVision (DE3468D) portable side scan sonar trawled on the “Saria” vessel with a high precision GPS system. The survey vessel performed a number of transects in the study sub-areas, in most cases parallel to the shoreline and with an overlap of the scanned area of the bottom between two adjacent transect lines. All data were continuously recorded onboard the survey vessel on a computer with the appropriate software systems installed. Additionally, the BlueRobotics, BLUE ROV2 (ver. heavy duty) underwater drone was used for ground truthing of the different habitat types. The sonograms of the scanned area were later used for the creation of substrate type maps of the area. Data analysis was performed with the software products DeepView Pro for the side scan sonar data, and QGIS3.12 for the creation of substrate and overview maps. Data exported in KML format by DeepView and transformed in shape files in QGIS. Polygons of the same habitat were merged so each feature within the shapefile is assigned to each habitat. To ensure that the data will display properly the shapefiles were cleaned by removing any geometry or topology errors. All habitats visualized on MedOBIS viewer (https://portal.lifewatchgreece.eu/).