This book offers the first in-depth sociological examination of the global phenomenon of action sports. It argues that trends in contemporary action sport cultures raise important questions about the changing nature of sport in the 21st century. Adopting a global ethnographic approach and engaging multiple theoretical perspectives, it examines how transnational action sport corporations, mega events and media spectacles, the international travel patterns of athletes, tourists and migrants, and the high use of social media among participants, are contributing to the emergence of a transnational imaginary within and across action sport communities. This book contributes to recent debates in the fields of transnationalism, mobilities and migration scholarship, by revealing both the macro structural features of transnationalism and the everyday lived experiences at the local level. Each chapter offers case studies and site-specific vignettes from an array of action sports and around the world. Ultimately, this book illustrates how corporeal, virtual and imagined mobilities and connections across borders are influencing not only how youth are practicing and consuming sport and physical activity, but also how such processes are informing their sense of space, place, identity, politics and belonging.