Weather ship routing has become a recognized measure to target safe, sustainable and economical ship activities. Academic research has focused the ship routing optimization through pathfinding algorithms which take into account the meteo-oceanographic forecasts (i.e. wind, waves or currents predictions). This contribution shows the results of the numerical simulations carried out during the development of a weather ship routing applied to a ferry service in the Mediterranean Sea: Barcelona – Palma de Mallorca. From a methodological point of view, the pathfinding A* algorithm is applied to optimize the travel time considering the wave action. Under severe weather conditions, a reduction of the 7% of the travel time is obtained comparing the optimized route and the minimum distance route. The results show also a non-significant correlation between the travel time reduction and wave height. In consequence the benefit of ship routing depends not only of the wave height but also in the spatial sequence of the storm.