Multibeam data were collected during R/V Polarstern cruise ANT-XI/4. Data recording was executed in South Atlantic and southern Indian Ocean between Cape Town and Astrid Ridge 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 12 files in ATLAS ascii multibeam format including 'record control words' (*.dux) which are compressed with GZIP to size of 133 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 ant11_4-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.