This chapter seeks to understand how the post-industrial developmental state is layering a new cosmopolitan diversity unto the old postcolonial multiracialism in Singapore in the smart town of Punggol and why it is believed this is necessary for urban transformation to an innovative high-tech smart city. We argue that is also important to discuss public reactions to the state project and the experiences of professional migrants who populate and work in these smart towns, and how these could undermine cosmopolitan diversity. Based on findings of our research into the experiences of professional migrant families living in Punggol and the neighbouring Seng Kang town, we argue that the urban planning for cosmopolitan diversity is inadequate. It is not “smart” enough to tackle the deep-seated social relationships between the high-tech migrants and locals emergent in the everyday life of ethnic relations and multiculturalism in the public housing milieu.