This study aims to clarify the process of the incremental regeneration of unutilised inner harbour areas in Japan. The way of gradual regeneration in inner harbour areas by renovating the old warehouses is being developed in the several ports in Japan recently. These examples (Tokushima-Komatsushima Port, Hiroshima Port, Oita Port) are characterized in the long-term conversion of the not highly historical valued harbour facilities and the cooperation between private companies, NPO and public sectors. Staged regeneration can reveal potentials of attracting people in inner harbour areas and stakeholders play their roles on enhancing the amenity of people's spending time there. Especially, developing the public spaces on seashore by public sectors is important for chaging the usage on piers.