Rapid response models for the assessment of the consequences of a radioactive spill in the coastal waters of Andalusia (south of Spain) have been developed. These waters comprise the Gulf of Cadiz, GoC, (Atlantic Ocean) and the Alborán Sea, AS, (Mediterranean Sea) and two models are described, covering both sectors. This subject is of high relevance since these waters are the only connection between the Atlantic and the Mediterranean. Thus, there are intense shipping activities that for instance include the transit of nuclear submarines. The models include hydrodynamic sub-models appropriate to describe the water circulation in each area. Results from the hydrodynamic models have been carefully tested through comparisons with observed tides and currents. The dispersion models are based upon a particle-tracking technique. Thus, the radioactive spill is simulated by a number of discrete particles, each one equivalent to a number of units, whose paths are computed. Turbulent diffusion and radioactive decay are calculated using a stochastic Monte Carlo method. The radionuclide concentrations may be obtained at the desired time from the density of particles per water volume. Some applications and examples of results are given.