Swath sonar bathymetry data were acquired during cruise AL652-2 with the research vessel RV ALKOR using a hull-mounted Kongsberg EM2040 multibeam echosounder (MBES). The cruise took place between 25.05.2026 - 02.06.2026 in the German Baltic Sea. The approximate depth range of the mapped area is between 15-30m. To improve MBES data quality, sound velocity profile (SVP) casts were conducted in the vicinity of the mapped area prior to and after each survey using a Sound Velocity Probe. The data set includes data from an area called 'Oejet', which is a part of the Nature Conservation Area (NCA) 'Fehmarnbelt', located in the western Baltic Sea. The survey was carried out to support baseline habitat studies in this region. Data processing involved the application of a weak spline filter and manual cleaning to remove erroneous soundings, performed using Qimera (https://qps.nl/qimera/#). A bathymetric raster was generated and exported in GeoTIFF format with a spatial resolution of 0.25 m (negative depth values), referenced to WGS84 as the vertical datum and projected in UTM coordinates. The dataset consists of two surveys (Stations AL652-2_65, AL652-2_77) that were combined into a single final grid.