A shoreline protection dike includes a plurality of juxtaposed protection devices each including a front face which is curved so as to deflect the water from each wave upwards and back in the direction of ebbing. The front face includes a concave curved shape formed by lines parallel to one another and extending between lower and upper edges of the front face, each line resting on a curved line which extends in a plane perpendicular to the lower and upper edges, the curved line including a first sector which forms a first arc and at least a second sector which forms a second arc.