While methadone maintenance treatment (MMT) has been effective in improving opioid use outcomes, most patients continue to engage in unhealthy lifestyles that lead to significant mental and physical health consequences. Interventions targeting increases in physical activity (PA) in MMT patients could have a significant impact on reducing the overall morbidity in these individuals. The purpose of this study was to assess acceptability and feasibility of a 12-week peer-facilitated PA intervention for MMT patients called TREC (Transforming Recovery with Exercise and Community).