Sand waves, defined as longshore wave-like movements of the shoreline, measured in a horizontal plane, are described along several stretches of the shoreline of The Netherlands. They have a celerity in the order of 50-200 m/yr, a period of 50- 150 years and an amplitude of 30- 500 m. They are found along the whole Dutch shoreline. Analysis of sand waves shows that the assumed effect of groins might be very small along this shoreline. There are indications that groins did not have any long-term effect on coastal regression.