Increased physical activity can have health benefits among inactive individuals. In Sweden, the healthcare system uses Physical Activity on Prescription (PAP) to motivate patients to increase their physical activity level. Mindfulness may further heighten the internal motivation to engage in physical activity. However, previous research has not demonstrated clear evidence of such associations.Aim: Examine the feasibility of the study design as a preparation for a full-scale study, and examine the differences, between three interventions, in change over time in physical activity levels and in related variables.Method: Comparison between three different interventions in an ordinary primary health care setting: PAP, mindfulness, and a combination of PAP and mindfulness. Physical activity was measured with self-report and ACTi Graph GT1X activity monitor. Statistical analysis was performed with a mixed effect model to account for repeated observations and estimate differences both within groups and between groups at three and six months follow-up.Results: Between September 2016 and December 2018, a total of 88 participants were randomised into three groups. Eleven participants were excluded from analysis due to low activity monitor wear time. The total dropout rate was 20.4%, the attendance rate to the mindfulness courses (52% > 6 times) and the web-based mindfulness training (8% > 800 minutes) was low according to the stated feasibility criteria. Self-reported leisure time physical activity showed a significant difference in change between the groups (p= 0.04); the mindfulness group did not report the same increase as the other groups. The activity monitor data showed no significant differences between the groups. However, within the combination group, there was a significant increase of percentage time in light physical activity, which was not found in the other groups. Among the secondary aims, self-rated health showed a significant increase only within the combination group.Conclusion: The study design needs adjustment for the mindfulness intervention design before a fully scaled study can be conducted. A combination of PAP and mindfulness may increase physical activity and self-rated health more than PAP or mindfulness alone.Trial registration: ClinicalTrials.gov, registration number NCT02869854. Regional Ethical Review Board in Lund registration number 2016/404.