This paper presents two-dimensional (2D) and three-dimensional (3D) numerical models for unsteady phased thermal analysis of RCC dams. The time evolution of a thermal field has been modeled using the actual dam shape, RCC technology and the adequate description of material properties. Model calibration and verification has been done based on the field investigations of the Platanovryssi dam, the highest RCC dam in Europe. The results of a long-term thermal analysis, with actual initial and boundary conditions, have shown a good agreement with the observed temperatures. The influence of relevant parameters on the thermal field of RCC dams has been analyzed. It is concluded that the 2D model is appropriate for the thermal phased analysis, and that the boundary conditions and the mixture properties are the most influential on the RCC dam thermal behavior.