There is a limited number of studies on the impact of mindfulness-based interventions on university students and their positive effect on collective experiences of shared flow. The aim of the present study was to explore the effectiveness of mindfulness training in terms of reducing stress and enhancing well-being, experiences of shared flow and classroom climate (engagement and affiliation). The intervention and control groups were matched by age and sex (n = 125; M = 20.71, SD = 4.60, 68% women). The intervention group comprised mindfulness exercises performed in the classroom over the course of 7 weeks. The principal variables were measured at pretest and posttest, and shared flow was also measured in the intervention group. In comparison with the control group, statistically significant differences were observed in the intervention group in relation to mindfulness, perceived stress, and classroom climate (affiliation). Furthermore, the perception of shared flow among students increased from the beginning to the end of the program. Mindfulness skills were found to mediate improvements in perceived well-being and stress. It is concluded that mindfulness practice can turn learning into a challenging and shared task. The study highlights the importance of fostering programs that enhance the development of competencies related to mindfulness among university students.