This study discusses the social dimensions of MPAs in Tanzania, using the case of the Mafia Island Marine Park and the socioeconomic, political and cultural contexts within which Mafia people live their lives. Based on documentary surveys and interviews with residents of the island’s villages, national government officials, and the park’s management, the study puts forth several proposals through which traditional, small-scale and artisanal coastal communities can engage better in protecting the marine ecosystem and their rights.