A mapping of wind and wave potentials of the whole Mediterranean basin, aimed at identifying the areas where wind and wave events are not time-correlated, was performed in order to plan offshore coupled wind-wave energy extraction. For this purpose, meteorological and marine conditions of the whole Mediterranean basin for the period 1979–2016 were obtained by means of WRF and WaveWatchIII simulations. More promising areas where to plan a hybrid installation for the joint exploitation of wind and wave energy resources were thus selected on the basis of a suitable statistical index. Such an index, combines information on the availability of wind and waves together with the degree of correlation of the occurrence of the two resources. The index will efficiently select the most interesting area in the Mediterranean Sea characterized by non-concomitant-in-time availability of wind and wave thus ensuring an optimized time-availability of the combined resources. Finally the power production of an hypothetical hybrid plant composed by different models of wind rotors and wave energy converters is evaluated for four test sites. The results of this analysis shows that the described index represents a useful tool for preliminary evaluation of areas where combined wind-wave energy extraction could be more profitable.