In the past applications of risk assessment for coastal structures; only wave characteristics, tidal range, storm surge, wave set-up, surf beat and structural system parameters were considered, but the tsunami risk could not be incorporated to the reliability based design in the literature. The reliability model REBAD introduced in this study primarily enabled the risk assessment of breakwaters subject to tsunami risk. The Second-Order Reliability Method (SORM) was applied to determine the safety of Haydarpa a Port, Sea of Marmara, Turkey. The failure probability was forecasted by approximating the Van der Meer failure surface with a second-degree polynomial having an equal curvature at the design point. Inclusion of tsunami risk that has an extended return period when compared to storm waves, increased the failure risk of the structure in its lifetime. For Haydarpa a port main breakwater, the failure risk of the structure was not sensitive to the tsunami occurrence. However, in places with great seismic activity, tsunami risk may be very significant depending on the occurrence probability and the magnitude of the tsunami.