From the theoretical perspective of ecological dynamics, skilful behaviour in performance contexts like sport and education is predicted on the establishment of a functional relationship between an individual and the environment. The strength of this functional relationship is shaped over time by everyday behaviours, values, and customs (sociocultural practices) within a specific sport organisation. A growing body of research seeks to identify these influential sociocultural practices that emerge and exist in sport cultures and organisations. However, little is known from an ecological realism perspective how these practices affect an athlete's engagement with opportunities offered by the environment (e.g. affordances). In this study, we draw on ethnographic data and theoretical tenets of James Gibson's ecological psychology to identify how the sociocultural practices of a British rugby league football academy might shape an athlete's engagement with affordances. Findings revealed that masculinity and disciplined behaviours were the dominant sociocultural practices, instrumental in developing beliefs, values, and customs of athlete development practices. An ecological realism analysis of the data suggested that cultural pressures meant that key actors ignored the potential for development and learning of athletes' self-organisation tendencies, and inhibited individuals' capacities to respond to opportunities for action offered in many traditional practice designs. We conclude by discussing implications for sport practitioners that promote 'affordance-regulated' practice designs to enhance athlete-environment interactions.