This paper directs attention towards the plethora of ongoing health and well-being initiatives that seek to address young people's participation in physical activity and that are underpinned by interests in youth health. Focusing on contemporary developments in the state of Tasmania and throughout Australia, the paper examines these initiatives by highlighting the complexities of health and well-being contexts relating to youth physical activity in Tasmania, and calls into question the extent to which complexities are acknowledged in these developments. Five assumptions are then identified and problematised in relation to contemporary and future health and well-being developments. These relate specifically to: (1) the importance and appeal of physical activity for youth; (2) accompanying agendas focusing on eating patterns; (3) the role of physical activity in countering overweight and obesity; (4) the identification of schools and education as prime sites for health and well-being interventions; and (5) the faith placed in "health and well-being interventions" as effective responses to current concerns about youth physical activity and health. Issues are raised for professionals and researchers with interests in youth physical activity and health to consider.