Simultaneous tidal current observation at five or seven stations on the channel near Incheon Habour was conducted at neap, mean and spring tides during the period of August 16 to August 27, 1976 and the characteristic of tidal currents with each tide was studied by the analysis of these data. Times of slack refer to the times of high and low waters at neap, mean and spring tides seem to be small. Times of maximum current refer to the times of high and low waters at the mean tide tends to appear earlier than that of the neap tide and later than that of the spring tide. The velocity ratio of maximum ebb current to maximum flood current at the mean tide has larger value than that of neap tide and has smaller value than that of spring tide. The current velocity ratio of spring tide to neap tide and to mean tide are approximately 1.8 and 1.3, respectively.