. Beach damages in the form of beach erosion, has been made problems in many countries. For solving the problem, the experts have been developed many kinds of structure, as revetment, grion and detached breakwater. Although a part of the structure succeed to restrain the beach erosion, but generally it is not friendly environmental, especially from the tourism view. This paper try to develop friendly environmental beach protection, by taking the coral characteristic, in the form of submerged breakwater. The analysis is focused in the capability of the submerged breakwater in reducing the incident waves, which be approahed by the relation of wave steepness Hi/gT2 versus transmission coefficient Ct = Ht /Hi , for certain b/L and d/h. The result is wave transmission figures, which show that the bigger value of b/L or d/h the smaller value of Ct.