University Students' psychological well-being can impact their health, academic performance, retention, and ability to complete university. Participation in peer mentoring well-being programs has been found to help improve student outcomes. This study aimed to explore student mentors' experiences of a co-designed university student peer-to-peer well-being program, the "Comfort Corner". The study utilised a sequential mixed methods design collecting survey and interview data from student mentors about their experiences, knowledge and attitudes about psychological well-being as well as their skills and confidence to support the psychological well-being of their peers. Thirteen student mentors completed pre-post program surveys which revealed higher post-program scores on assessments related to their perceived communication skills (pre-test M=84.3, SD=13.7, post-test M=86.7, SD=11.5) and their knowledge about psychological well-being (pre-test M=10.9, SD=5.4, post-test M=15.6, SD=2.7). All 8 student mentors who completed a post-program satisfaction survey indicated that the peer-mentoring program improved their skills and was very useful (100% respectively). Thematic analysis of interviews conducted with 10 student mentors revealed 2 themes, 1) understanding psychological well-being and, 2) knowing how to engage and help others as accounting for improvements in student mentors' skills and knowledge. Student mentors described their experience with Comfort Corner under a central theme, 'fostering a community of support for students on campus', they felt Comfort Corner provided welcoming, safe, and supportive space for students. These findings revealed the benefits of co-design using a student as partners framework for a peer mentoring well-being program in improving areas of student mentors' skills and knowledge as well as promoting a sense of belonging and connection for students enrolled in higher education.