The analysis of stone artefacts from the open-air localities of Geelbek and Anyskop in the Western Cape of South Africa offers new insight into the behaviour of Middle Stone Age hunters and gatherers. We examined five deflation bays in these mobile dune systems which, in contrast to caves or rockshelters, display large-scale spatial patterning with regard to the distribution of lithic artefacts and faunal remains. The definition of raw material units enabled us to reconstruct the patterns of production, use, and discard of stone artefacts. The results reveal that hunters and gatherers, such as those who produced Howiesons Poort stone artefacts, employed diverse planning strategies in terms of raw material exploitation, transport technology and site use. Although the faunal remains are not yet fully evaluated, the presence of stone points and segments suggests that hunting played an important role among the activities documented at Geelbek and Anyskop. The low number and heterogeneity of the stone artefacts suggest that people of the Middle Stone Age were highly mobile.