The purpose of the present research is to study tidal flows in Merimus estuary. Having direct access to the Persian Gulf from north and south, this estuary has a very special potential. In this paper, field data of water level, suspended sediment concentration, velocity and direction of flow, and the physical characteristics of temperature, salinity and density of the Merimus estuary in two complete tidal cycles (spring tide and neap tide) have been studied in two stations. At the first station, water level changes in spring tide and neap tide were equal to 5.9 and 5.7 m, respectively. At the second station, these changes were equal to 4.3 and 4.4 meters for spring tide and neap tide, respectively. At the first station, maximum flow rate in spring tide and neap tide was equal to 0.42 and 0.26 meters per second, respectively. At the second station, this rate was equal to 0.64 and 0.64 meters per second for spring tide and neap tide, respectively. There were many changes in density and salinity level in channel and maximum measured density and salinity were equal to 1034.34 kg/m3 and 49.75 PSU, respectively. Average sediment transport at different depths in spring tide and neap tide were equal to 67 and 153 mg/l, respectively.