Background: Therapeutic climbing (TC) has been increasingly implemented in the context of mental health care, with promising effects. While most evaluation studies focus on symptom reduction, the specific elements and mechanisms that make climbing effective compared to other therapeutic sports remain unclear. This study explores the subjective experiences of participants of a climbing therapy program in order to explore the underlying processes and the subjectively perceived effects. Method: The study took place at an inpatient rehabilitation facility in southern Germany, where a weekly group TC program was part of the treatment for individuals with mental disorders. Data from 265 participants with ICD-10 mental disorders collected between 2010 and 2022 was analyzed via questionnaires quantitatively assessing physical, psychological, and social improvements with rating items. Additionally open answers on subjectively relevant psychological experiences were analyzed using a qualitative content analysis. Results: Climbing therapy was generally perceived as relevant to their rehabilitation and rated as influential in terms of improving physical and psychological condition as well as sociability. The qualitative analysis identified five main categories being “Successful coping and positive mood”, “Challenge and coping strategies”, “Self-reflection and self-perception”, “Social experiences and belaying” and “Letting go of worries and being in the moment”. Conclusion: The results support previous findings on the benefits of TC and highlight its relevance as a therapeutic tool. Participants with mental disorders reported various positive experiences, emphasizing the unique demands, motivational aspects and social context of climbing. Further high-quality research is needed to compare climbing’s potential with other therapeutic sports across different target groups.