The knowledge of the marine seabed and subsoil characteristics and properties is essential for the correct development and design of any structure to be installed offshore. In this sense, geophysical techniques are indirect methods that allow obtaining high quality data useful to investigate the seafloor and therefore assure an optimum installation and maintenance of the cable route line (RPL) of submarine electrical cables connections. When a submarine cable route is investigated, it is planned to find if the pre-defined cable route is suitable and if there are any potential constrains that can cause problems or injuries during the installations works or during the further maintenance. Therefore, it is important to define any possible installation constrains based on the geophysical (and geotechnical) data throughout the cable route. In this work, it is presented the methodological approach for geophysical investigations for inter-array and export cables in offshore wind farms as well as for any submarine interconnection cable between different regions. The results obtained with MultiBeam Echo-Sounder, Side Scan Sonar, Sub-Bottom Profiler and Magnetometry are presented when they indicated potential constraints that can affect these infrastructures like boulders, seabed steepness, bedrocks outcrops or unexploded ordnance and manmade objects.