Before excavations were carried out of the rocks and dredging spoils for extension of the Porto-Vecchio marina in Corsica, France, an investigation was carried out by the Subaquatic Office of the French National Institute for Preventive Archaeological Research. SHOM (Service Hydrographique et Océanographique de la Marine, Ministry of Defence in France), who specialised in Hydrographic and Oceanographic services, recommended that the project team couple the sub-bottom profiler with a multibeam echo sounder. In preventive archaeology, time pressure is a significant factor in your need to compile a large volume of data. Archives such as archival maps, old spatial data and data from more recent surveys including meta-data from a sub-bottom profiler and multibeam echo sounder, can be superimposed on the dataset of current marine maps after which all statistics can be integrated in a Geographical Information System (GIS). All of the processed data were exported in QGIS®TM. The GIS allowed us to subdivide or categorise the abnormalities according to different parameters. GIS is a meta-data compilation tool—a guide for archaeologists to strategically choose what to excavate.