This paper examines how Islam in Japan tends to be tolerated as (foreign) “culture,” especially within the framework of tabunka kyōsei, multicultural coexistence, and cosmetic multiculturalism to circumvent religious apathy, phobia of religion, and prejudice against Islam. In doing so, this paper will: first provide a history of Muslim–Japanese relations and Muslim communities in Japan as well as an overview of the total estimate of the Muslim population in Japan as of 2018; historicize and denaturalize religious apathy, phobia of religion, and prejudice against Islam among the general Japanese public; analyze the rhetoric of tabunka kyōsei and its relation to cosmetic multiculturalism as well as its problematics; investigate the cases of local oppositions to the building projects of mosques and my observations made at events organized by Muslim groups; and conclude with a critical remark on the cosmetic multiculturalist understanding of “Islamic culture” and its approach to tabunka kyōsei.