The flow and sediment transport over a reversing ~ 7 m–high barchan dune in China is examined. Velocity profiles are non-logarithmic and jets occur at the dune crest. Speed-up across the windward slipface is significant with a ratio of 5.25. Maximum total sediment flux occurred at the dune crest. Significant sedimentation takes place downwind on the leeward dune surface due to a sand plume streaming from the dune crest.