In the applications of reliability-based risk assessment methodology in Turkey, only wave characteristics, tidal range, storm surge, wave set-up, and structural system parameters were included in the past. Tsunami risk was not considered as a major design parameter and thus, was not included in the computation. After a strong earthquake (M-w = 7.4) occurred near the town of Golcuk, Izmit Bay, Western Turkey at 00:01 GMT on August 17, 1999, chaotic water movements were observed on the coast of the Marmara Sea. Rubble mound breakwaters demonstrated very little damage, as predicted by the reliability-based risk assessment model developed in this study for the Tuzla Naval Base. For determination of the probability of occurrence under design conditions, which is a function of storm waves, tidal range, storm surge, and tsunami height, the Monte Carlo simulation was interrelated with the beta(II) method. For the Tuzla Naval Base main breakwater, tsunami was not the key design parameter when compared to storm waves, however, in places with great seismic activity, tsunami risk can be significant depending on the probability of occurrence and the magnitude of the tsunami.