Ethnic migration policy is rarely examined in labour market and migrant entrepreneurship research. The phenomenon of return migration among third generation 'dekasseguis', who are Brazilian citizens of Japanese heritage, represents one solution for Japan's struggle with its economic future. We examine the integration of ethnic migrants into Japanese society and economy employing multiple methods. We discovered significant roles of historical ethnic ties and transgenerational diaspora, but also found unsupportive and discriminatory policies, questioning the sustainability of these practices. Existing Japanese social and cultural integration programmes do not match the diverse needs of different generations of reverse diasporans and co-ethnic returnees. Further, considering factors such as language proficiency, country of origin, previous residence, duration of residing abroad, professional experience, education, and plans for settlement would foster societal integration, international business, and the Japanese economy.