EnBW Ostsee Offshore GmbH is planning the installation of 80 offshore wind turbines within the wind farm Kriegers Flak about 30 km north off the Island of Ruegen in the Baltic Sea. The water depth within the proposed area varies between 20 m and 40 m. FUGRO was awarded to perform the main geotechnical site investigation according to the BSH standards following a preliminary investigation conducted in 2005. The geotechnical site investigation comprised the performance of a total number of 55 boreholes to maximum depths down to 76 m below seabed. Explorations were performed either with wireline coring or with combined sampling and discontinuous CPT testing in quarternary sediments as well as in cretaceous carbonates.The recently completed field exploration program was conducted using the drilling vessel M.V. Highland Eagle together with the "Goliath" Jack Up Platform.The wireless down-hole system WISON XP was applied for the discontinuous CPT's, the Geobor S Coring System combined with the WIPSAMPLER for sampling the upper layers.Using this system almost 100% sample recovery was conducted. The fieldwork was carried out between November 2009 and March 2010 under the overall management of the GeoEngineering Department of FUGRO CONSULT GmbH Germany.