The coastal currents of the Persian Gulf were simulated using a Coupled Hydrodynamical Ecological model for Regional Shelf Sea (COHERENS) numerical model with horizontal resolution of 2 min latitude and 10 sigma vertical layers. Persian Gulf coast line and bathymetry data based on ETOPO2 and also atmospheric data extracted from NOAA were applied to the model. To validate the model simulation results, salinity field in winter and summer was extracted from the surface to 15 meter depth and compared with Reynolds (1993) results. The horizontal current strongly depends on hydrography fields, especially the field of salinity. Surface salinity fields clearly show seasonal variations in the influx amount of water from Indian Ocean and its conversion into saline water. There are extreme seasonal variations in addition to the general water circulation in the Persian Gulf. The simulation results showed that the intrusion of Indian Ocean surface water into the Persian Gulf gradually increased from January to June and it is the highest in June. It then in July and August began to decreases. Due to the influence of salinity flux, especially in the coastal part of Iran, the velocity of currents increases as well. The velocity of currents decreases from January to March and begins to increase from May. This trend continues until June and July and then began to decrease in August. The model results showed that south-eastward current along the coasts of Kuwait and Saudi Arabia was stronger in spring and summer than in other seasons. This current is completely weakened in winter due to the thermohaline and wind-induced currents. The simulation results showed three cyclonic eddies in September, approximately 100 kilometers in diameter, which is in good agreement with the MODIS sensor and AVISO satellite images. This cyclonic eddies cover the entire water column. Fully expanded of this eddies formed in the summer months.