This paper deals with the estimation of the sea state parameters thanks to the measurements collected by a X-band nautical radar. In particular, the paper presents the results of the processing of the data collected by the radar systems installed at different locations of the Italian peninsula. In fact, thanks to their flexibility and capability to monitor the sea surface, these systems represent an useful observational tool for a number of applications, which span from the quasi real-time estimation of parameters for the safety of harbours to the validation/calibration of the numerical models aimed at the prediction of the propagation of the sea waves towards the near-shore areas.