Key Messages• Prisoners' participation in sport and exercise is socially significant to the production and contestation of carceral space. • Sport can enable prisoners to cope in various ways with their incarceration, yet it can also contribute to the construction of violent and exclusionary spaces. • The folding of sport spaces into carceral spaces may be complementary, but will not necessarily contribute positively to the social development or well-being of inmates.Sport and exercise are prominent activities in the daily routines of prisoners around the world, yet the spatial significance of these activities in carceral environments has not been deeply investigated. With a focus on the experiences of former federal prisoners in Canada, this paper addresses this scholarly gap by bringing together emerging trends in the literatures on sociology of sport, sports geography, and carceral geography to investigate the complex social meanings of prison sport and exercise. Specifically, we explore the folding of sports space into carceral space, often with the effect of reinforcing violent and exclusionary situations, but which also helps construct alternative spatial and temporal realities. Indeed, our overarching theoretical analysis considers how prisoners use sport to produce space in ways that assert a limited degree of agency over their daily lives and temporarily transcend their unpleasant conditions of confinement. By drawing from diverse theoretical frameworks and literatures, we advance novel arguments about the socio-spatial significance of sport in prisons and raise some important questions for further research.