There is strong evidence that physical activities (PAs) are an important factor in increasing and maintaining mental health as well as in preventing relapse after mental health disorders. Physical activity is an important part of the treatment program in psychiatric hospitals. However, when individuals with mental health disorders (IMHD) leave the hospitals in Switzerland (CH), there are few possibilities to do physical activity in a given setting. One of them are voluntary sports groups for individuals with mental health disorders (SGPSY), which have been growing continuously in CH since 2016. Yet, little is known about these groups and their training settings. Therefore, the present study explores challenges, barriers, and enablers for participation in SGPSY from the point of view of the trainers of these groups. Additionally, as the sustainable implementation of SGPSY relies on the trainer, the study aims to identify reasons/motivations as well as the personality characteristics of the SGPSY trainers. Semi-structured interviews were conducted with 15 trainers of SGPSY in CH during spring 2022. Interviews were audiotaped, transcribed, and analyzed using thematic analysis in nVivo. Participants identified several intrapersonal (lack of motivation and fitness, mood problems, etc.), interpersonal (conflicts between participants), and structural barriers (time/location) that hinder IMHD from participating in SGPSY. The participating trainer reported that trainer might be helpful in overcoming the barriers by supporting IMHD as enablers. They rate social skills to be essential for the successful management and organization of SGPSY, as well as the ability to set boundaries to protect one’s private life and sports skills expertise. The reasons for their engagement as trainers of SGPSY were the satisfaction of doing sports with IMHD and to improve the physical activities habits of IMHD. The findings of the study highlight the need to upskill the trainers of SGPSY in order to improve recruitment of the future trainers of SGPSY by focusing on the assessment of appropriate personality characteristics of trainers and their motives. Additionally, these findings should be integrated in the educational materials of Swiss disabled sports systems. Further research should validate the results from SGPSY participants’ point of view.