Abstarct: Abstract The coasts and ports protection has always been an important and complex issue for engineers. There are many advantages in using soft and quasi-soft methods over hard and structural methods. Submerged breakwater as a quasi-soft structure with many environmental advantages and the possibility of further preserving the natural situtaion of the coast, is an important solution in coastal protection and preventing waves from entering the port basin. In this study, the effectiveness of submerged breakwater on wave penetration control in Chabahar Bay region has been evaluated. In this study, first the initial conditions were modeled using Mike21 BW Module. Then, using calibration parameters including sponge laxyers, porous laxyers and wave production lines, the initial model were validated. In the final step, baxsed on the results obtained from the initial model, the effect of different scenarios of submerged breakwater varing in dimensions and types of cross-section geometries were examined and compared. The results of these scenarios showed that in addition to effects of presence of this structre on reducing the penetration of waves in the port basin, including porosity in this structure has a significant effect on the dissipation of incoming waves. From the aspect of varing of the wave height value during the modeling, the best performance for keeping the wave height value in a small range was obtained by using step and trapezoidal cross-section, respectively, and the worst performance was created by rectangular cross-section.