A study has been conducted to estimate the appropriate value of the seismic forces applicable for the stability analysis of berths in the Eastern zone of KSA. Since KSA does not have a specialty code for the design of coastal structures, relevant international coastal codes have been called in the design of concrete gravity-type quay walls and the Saudi Building Code (SBC 301). The Japanese standards for the design of port facilities (2009) as well as the Coastal Engineering Manual, British Standards (BSI) and Uniform Building Code (UBC) have been called. It has been found that horizontal forces in the range of 1~4% of the structure weight are developed on the quay walls depending on the soil type and degree of occupation / possible hazards. Both ordinary and extra-ordinary cases of loading have been considered. The use of the Japanese code produces stable and economic sections; however, the BSI produces more conservative design of the quay walls. It has been concluded that the case of seismic forces is not the critical case of loading in the Eastern zone of KSA and the BSI requires about 15% of the concrete volume more than the sections computed by the Japanese code.