The present paper deals with an experimental investigation focused on the comparison between the effectiveness of different prefabricated caissons to the aim of reflection reduction. Motivation of the work has been the necessity to choose the optimal caisson type for wave energy dissipation to be adopted in the enlargement of the harbor of Siracusa (Italy). By comparing perforated caissons with prefabricated caissons with internal rubble mound (combined caissons), it has been found that for the range of parameters that have been analyzed, the combined caissons generally behaves better in terms of reducing the wave reflection than the perforated ones, especially when the caisson geometry is such to guarantee a mild slope of the rubble mound.