Chabahar Bay is a semi-closed and shallow bay in southeastern of Iran and is strongly affected by the monsoon conditions. The 3D FVCOM model was used to study the hydrodynamic conditions of Chabahar Bay. For this purpose, a horizontal grid with 6290 triangular elements and a vertical grid with 10 sigma layers were created. The model was implemented in baroclinic mode; NCEP data and HYCOM model outputs were used to account for open surface and boundary layer forces. Water level and flow velocity correlations show acceptable agreement with field data. The tidal bay is often semi-daily and mixed and the tidal range is 2.7 m. The flushing time of Chabahar Bay was calculated to be 6.7 days. The modeling results show; The vertically and annual average current velocity is 0.1 m/s and the rotation pattern is often anticyclonic.