Mindfulness is a meditative practice that has received increasing attention within positive psychology as an effective tool to increase wellbeing and decrease anxiety. Previous research has demonstrated that rock-climbers have a higher endorsement of mindfulness and life satisfaction than the general population; yet to date, no research has empirically explored the relationship between mindfulness and rock-climbing. In the current study fifty-nine participants ($$ \overline{\mathrm{x}} $$ x ¯ = 20.63, SD = 1.60) were asked to complete measures of mindfulness, wellbeing and anxiety before and after participating in an ‘intervention’. The intervention consisted of a mindfulness activity followed by either indoor bouldering (a form of rock-climbing) versus a physical activity control. A mixed ANOVA revealed that participation in bouldering increased the measure of mindfulness significantly more than the control activity; however, no significant group differences were found for the measures of wellbeing and anxiety. A regression analysis then revealed that group condition accounted for 33% of the variance in post-intervention mindfulness levels when controlling for baseline levels of mindfulness. This is the first study to experimentally demonstrate that engagement with rock-climbing increases mindfulness in young adults. Theoretically, the results have implications for our understanding of “flow” and optimal human experience. Practically, the study highlights the potential to implement rock-climbing as a resilience-building activity and integrate the sport within therapeutic frameworks.