Mindfulness interventions within sport have seen a rise in recent years, with face to face programs being delivered, one area that has yet to be studied is the use of mindfulness apps within sport. This study investigated the efficacy of a mindfulness smartphone app on mindfulness, flow and cycling performance. This study used a single subject multiple baseline across participants design (N = 6). Visual and graphical analysis revealed an increase in mindfulness in sport (MIS) and flow state (FSS-2 Short) scores, an increase in performance measures and a decrease in rate of perceived exertion (RPE). The findings suggest that smart phone mindfulness apps can increase mindfulness and flow state within cyclists, and influence performance measures with further research needed to understand the mechanics of the effect and how that changes over longer periods.