Physical activity (PA) community-based programmes are increasingly put forward to promote active, healthy lifestyles and bring about long-lasting benefits to beneficiaries (Wiltsey Stirman et al., 2012). Programme sustainability refers to the maintenance of an intervention beyond the initial time, resources, or other inputs to support it. A range of factors contribute to sport/PA programme sustainability; however, research often overlooks the critical ingredients to long-lasting interventions (Estabrooks et al., 2011). This study explores the elements that promote, or hinder sustainability of a walking-based intervention addressed to caregivers and care-recipients in Kent, United Kingdom. Drawing on interviews and focus group data with organisers and participants, findings were grouped under three overarching themes: Benefits on social and mental well-being, factors facilitating programme engagement and key implementation considerations. In discussing these findings in context, we provide implications for the sustainable planning and implementation of future community sport and PA programmes.