Multibeam bathymetry raw and processed data (RESON Seabat T50Extended Range) of Research Vessel Littorina at Fehmarn Belt in the western part of the Baltic Sea. The raw data (.db format) were processed using QPS Qimera software (v 1.7), based on the following workflow: 0.Raw data -> 1.Apply correct Sound Velocity Profiles -> 2. correct lever arm offsets -> 3. Finalize with manual 2D and 3D point editing. The corrected soundings were used to create a GeoTIFF (EPSG Code:4326) .gsf data and GeoTIFF are provided.