The circulation in the vicinity of an idealized tidal inlet connecting a continental shelf and a coastal sound is examined. The circulation is forced by an M2 tide and a weakly buoyant discharge. The buoyant discharge forms a plume in the coastal ocean and induces a distinct anticyclonic circulation at the plume edge that is maintained throughout the tidal cycle. We focus on the plume's onset and its evolution over 5--10 tidal cycles. Over the timescales considered, the plume was roughly circular, slightly skewed in the along-coast direction. The model solution yielded high vertical Ekman numbers Ev~O(5) in the vicinity of the inlet mouth, decreasing seaward from the inlet to an order of magnitude smaller (Ev~0.25) at the seaward edge of the plume. Passive particles released in the region seaward of the inlet mouth were used to describe the exchange between the coastal region and the inlet. A marked asymmetry between ebb and flood flows is observed in the vicinity of the inlet, with jet-like ebbing currents and weaker potential-flow-like flooding currents. Over a tidal cycle, net exchanges between the coastal ocean and the inlet are found to be spatially and temporally dependent; that is, particle trajectories depend on the release point and the time of the release in the tidal cycle. The near-inlet residual circulation shows significant differences in the absence of stratification. ¿ American Geophysical Union 1996.