Multibeam data were collected during R/V Polarstern cruise ANT-IX/2. Data recording was executed on transit from Punta Arenas to Austaasen Bank, Neumeyer Station and to Cape Town and was supervised by three hydrographers. Data are unprocessed and may contain outliers and blunders. Therefore the data should not directly be used for grid calculations and charting projects but need to be edited furthermore. The dataset consists of 13 files in ATLAS ascii multibeam format including 'record control words' (*.dux) which are compressed with GZIP to size of 57.8 MB. Atlas DUX data files can be processed using the open source software package MB-System (http://www.ldeo.columbia.edu/res/pi/MB-System/). Values of depths and lateral distances are averaged with neighbouring beams. The file ant09_2-hyd.tar.gz includes the bathymetry in AWI Hyd-format (hdl:10013/epic.37976) including not averaged depths and lateral distances. Contact mailto:infobathy@awi.de for data access.