The aim of the study was to quantify the effects of the wave period on dune erosion. Attention was focussed on 2D cross-shore effects in a situation with sandy dunes and extreme wave conditions. Large-scale physical model tests were set up to provide the necessary data for the study on a scale as close to prototype as possible. It was concluded that a longer wave period leads to a larger dune erosion volume and to a larger landward retreat of the dune face.