Ice-nucleating particles (INPs) significantly influence aerosol-cloud precipitation interactions at regional and global scales. However, information regarding the concentrations and origins of INPs over the open ocean, particularly at high latitudes, remains insufficient due to access difficulties. In this study, we investigated the concentrations and origins of INPs over the western North Pacific to the Arctic Ocean through ship-borne observations conducted in the early autumn of 2016. The number concentrations of INPs (