The effects of tides on the seasonal fluctuations and regional differences of the sea ice cover in the Weddell Sea are investigated using a dynamic-thermodynamic sea ice model operating at high temporal and spatial resolution. Tidal currents add a highly variable stress force at the ice-water interface. They are derived from an eight-constituent barotropic, ocean-only, tidal model. Thermodynamics are calculated for seven ice classes plus open water; dynamics consider an averaged ice class and open water only. Results from runs of the sea ice model with and without the additional tidal stress demonstrate that tidal currents alter the local and, to lesser extent, basin-wide evolution of sea ice. The tidal currents reduce the expansion of the ice cover, mostly cause a speed up of the retreat, and lead to a smaller minimum ice extent. The most significant local differences between the two model simulations are found in tidally active regions over the continental shelf breaks of the western Weddell Sea, in front of Filchner-Ronne Ice Shelf, and offshore Dronning Maud Land. Copyright 2005 by the American Geophysical Union.