For a fishing vessel, weather information is necessary to ensure safe navigation and to obtain fishing information. On board, fishers use the information on waves, winds, currents and water temperature on the basis of their experiences. Weather routing is one of the method to determine minimum time route or minimum fuel consumption route by using weather information. Recently, weather routing has become an important concept not only safe navigation but also energy saving for a fishing vessel. Thus, since 2014, we have been researching and developing a high-resolution weather routing system for a fishing vessel. We modified the weather routing system of merchant ships for fishing vessels by using a detailed grid size of weather information and incorporating a short calculation interval. This study examined the possibility to apply the weather routing to an actual fishing vessel, a skipjack pole and line fishing vessel, on the route between fishing port and fish ground, which is offshore of the Boso Peninsula in Japan. We introduced the high-resolution weather routing system on board. The results demonstrate that the weather routing can influence energy efficiency, and assist in fishing trip planning, to decide a departure time for fishing grounds.