This dataset includes high-resolution bathymetric data in numerical form (xyz) and depth given in m for a not previously covered (at this resolution=50 m) 4970 km^2 area of the Ionian Sea (Italy). The study area is located on the upper part of the continental slope of the Calabrian-Ionian margin between 120 m and 2000 m water depth. Dataset represents results of multibeam survey carried out during the Seismofaults 2017 cruise using a multibeam Teledyne Reson SeaBat 7160 (41-47 kHz; footprint size of 1°× 1°) echosounder. We identified precise positioning through differential GPS (accuracy ±0.5 m), while we derived sound velocity profiles from multiple Conductivity-Temperature-Depth (CTD) casts (Seabird 911plus) to ray trace the acoustic wave along the water column. We processed multibeam data on board using Caris Hips & Sips hydrographic software (Bosman et al, 2015) We used backscatter images and observations of raw data scattering along the water column to verify anomalies of amplitude on the seafloor and along the water column. The resulting dataset is presented in ASCII format and included in the following files: bathymetry_seismofault.txt (contains coordinates (°) - col1:lon and col2:lat (WGS 84, DD) - and seabottom depth (m) - col3 -). A detailed description of the scientific background is given in Cuffaro et al. (2019) to which these data are supplementary material. For technical reference, please consult the data description file.