Prestige fuel oil tanker was damaged during a storm in November 13rd, 2002, close to the coast of Galicia (Spain). After some days the Prestige broke in half and sank, leaking about 40.000 tons of oil which affected more than 1.000 km of the coast in Spain, Portugal and France. Some months later, layers of fuel contamination still appear at different depths in the sand of the beaches. The tidal process is that the first tide brings fuel over the sand but, if it is not removed, following tides place clean layer of sand on the top of fuel, and the beaches appear to be clean. Layers of fuel appears at different depths in the sand, from some cm to 1-2 meters. The lateral extent of the contamination also varies from some cm to more than 1 m. Radar sensors could be used in-situ to detect and imaging fuel layers below sand in some inland areas, which are under the influence of high winter tides but remain out of the influence of salt water from the sea during spring and summer time. This study show some tests carried out on the beaches with a ground-penetrating radar system operating with 500 & 800 MHz nominal frequency antennas, and a study case made in the beach of Carnota (Galicia) where it was possible to detect an imaging a buried fuel layer 6 months later.