ABSTRACT Background Mindfulness-based interventions can successfully improve wellbeing in young adults. Mindful colouring is an applied mindfulness practice and improves short-term wellbeing. Less evidence is available about the effectiveness of regular, self-guided colouring. We investigated a self-guided two-week colouring intervention for university student wellbeing. Methods One-hundred and forty university students completed a minimum of 10-min self-guided colouring, six times over two weeks. Participants were assessed at baseline and two-week follow-up using self-report measures of wellbeing, relating to quality of life, perceived stress, anxiety, depression, and mindfulness. Results Colouring significantly improved all measures of mental health, wellbeing and mindfulness in students who completed at least six sessions of self-guided colouring. Conclusion Colouring is an accessible activity that can improve student wellbeing when carried out regularly over two weeks. Future research should investigate the impact of longer-term colouring practice on wellbeing, and the effect of this intervention in the general adult population.