BACKGROUND: Despite improvements in pain and physical capacity experienced by patients following total hip arthroplasty (THA) and total knee arthroplasty (TKA), recent studies suggest that levels of physical activity may not change. This study aimed to qualitatively explore people's beliefs and perspectives about physical activity at 6 months following THA or TKA for the treatment of osteoarthritis (OA). METHODS: Semi-structured interviews were conducted with 10 participants (age range 51-78 years) at 6 months post-arthroplasty surgery. Participants were recruited from a concurrent larger quantitative study examining quantitative physical activity levels via accelerometers. Interviews were transcribed, coded and analysed using a thematic approach. RESULTS: Participants described greater capacity to be physically active post-surgery despite no increase in objective measures. Three themes emerged from the interviews relating to the participants perspective of physical activity after surgery: (1) physical activity is for enjoying living; (2) new limitations on physical activity: age and comorbidities; and (3) personal beliefs about physical activity: it is enough to know you can. CONCLUSION: Individual beliefs and perceptions are important in understanding factors influencing physical activity following THA and TKA. Health practitioners should examine this when developing management plans aimed at optimizing physical activity.