To advance understanding of the geographies of age segregation, this paper examines the intersectional social dynamics of age-segregated environments, considering how migration interacts with age segregation to breed sameness or diversity in ageing environments. We juxtapose findings drawn from two research projects, the first on international retirement migration in Spain, where older people inhabit certain geographical and social spaces with “people like them” sharing similar identity characteristics and preferences. The second project was in older people's centres in South London, more diverse sites where people are brought together on the basis of need rather than choice. In interrogating the different social dynamics operating in these age-segregated environments, we reflect on the implications of “choice homophily” for ageing experiences. We recognise the potential of differentiated spaces for ageing, but also question how homophilic choices in retirement can create self-selected and socially segregated retirement environments that reproduce divisions of “race” ethnicity and social class, which would undoubtedly be seen as problematic in other spheres of the life course.