Geoelectrical investigations to identify and characterize local geological conditions found in the area of undercrossing the Danube through horizontal directional drillings. The geoelectrical measurements were performed on water using cables and devices specially designed for this kind of work. Taking into account the Danube’s characteristics in the research area – width of 500 m, flow speed, intense sailing – the geoelectrical measurements were performed in Vertical Electrical Sounding (VES) method using two boats. Locating the exact position of VES was performed with a RTK GPS with high precision and water depth was measured using an Ohmex sonar. The results of these investigations have resulted in an interpretive geological section necessary for designing the future horizontal directional drillings.