This paper describes the Numerical and Physical Modelling components of the main project entitled "Viability study of the artificial surfing reef of S. Pedro do Estoril". These studies aim to establish the main characteristics (dimensions, orientation and location) of the artificial surfing reef for S. Pedro do Estoril and to analyze its hydrodynamic peifonnance for different incident wave conditions. The main conclusions of both studies were that the reef solution permits the improvement of the surf conditions in the area of S. Pedro do Estoril especially for the most frequent wave in the region. However, in both studies some problems related with strong reflection and vortices in the reef's corners where detected and should be improved in the final solution.