Multibeam data were collected during RRS James Clark Ross cruise JR17003a (2018-02-22 to 2018-03-12). Multibeam sonar system was Kongsberg EM122. Data are unprocessed and may contain outliers and blunders and should not be used for grid calculations and charting projects without further editing. The raw multibeam sonar data in Kongsberg multibeam processing format (*.all) were recorded with Kongsberg SIS software running on Windows operating system. Kongsberg data files can be processed using the software packages CARIS HIPS/SIPS or with the open source software package MB-System.