Tidal prism - cross sectional area relationships and tidal velocities have been measured for inlet entrances and along the length of the estuary for four creeks entering the sheltered waters on the South East Queensland coast, Australia. It has been found that the inlet entrance tidal prism - cross-sectional area relationship is controlled by the magnitude of littoral drift. The tidal prism - cross-sectional area relationship along the estuary is believed to be common to all tidal estuaries landward of the region where littoral drift has an influence. For tidal inlets on sheltered coasts with tidal prisms of the order of 10 n~, the mean maximum velocity entrance is about 0.3 to 0.4 m/s.