Background <p>Walking for leisure is a key contributor to healthy ageing, yet participation remains uneven across older populations. Addressing these inequalities requires approaches that capture how physical and social environments jointly shape opportunities for walking. Integrating the COM-B (Capability, Opportunity, Motivation-Behavior) model’s emphasis on behavioral opportunity, this study examines how the combinations of geographic and social domains intersect to shape walking in later life.</p> Methods <p>Conceptually grounded in the geosocial framework, which posits that territories (e.g., parks, walkways, libraries), social networks (e.g., social trust and bonds), and social categories (e.g., age and gender) intertwine to shape health and well-being, multilevel models were analyzed to examine the association between interlocking geosocial environments and walking using data from the National Health Interview Survey for adults aged 55 or older (<i>n</i> = 14,149).</p> Results <p>Collectively the three geosocial domains were interdependent, while individually territorial characteristics showed the strongest associations with walking for leisure, followed by social network and categorical characteristics.</p> Conclusions <p>By integrating the geographic and social opportunity domains of the COM-B model through the geosocial framework, this study quantitatively operationalizes the built, network, and categorical domains as interacting structures at a fine level of granularity to inform precisely targeted physical activity interventions among older populations.</p>