The present paper presents an experimental study of wave transmission for a trapezoidal submerged porous breakwater located in the nearshore region. Wave transmission characteristics of the breakwater subjected to unidirectional monochromatic waves have been ascertained via a systematic test program. A series of tests have been conducted to study the effect of porosity of the breakwater on wave transmission, and to assess wave attenuation performance of the breakwater in relation to wave steepness and the relative breakwater width. The test results have indicated that the breakwater of 20 porosity offers the highest hydraulic efficiency, and the breakwater provides higher wave suppression ability when exposed to shorter period waves particularly in shallow waters. © (2014) Trans Tech Publications, Switzerland.