While many scholars agree that service learning is beneficial to both the student and the community, the research on service learning in the physical education setting is limited. However, there are courses that can be aligned with the professional preparation needs of students and the broader needs of the community. Drawing on theory which has guided experiential education, the study examined what the students learning to teach young adults with disabilities consider meaningful when teaching, and how perceptions regarding disabilities evolve during a field experience that incorporates service learning and critical reflection. Fifty undergraduate students enrolled in an Adapted Physical Education course partnered with 24 young adults with disabilities for 10 weeks of biweekly cardiovascular and strength and conditioning instruction. Data were collected qualitatively and grounded theory approach guided the analysis of the critical incident reports, reflections, interviews, and direct observations. When analysing data, three distinct stages of development emerged illustrating students' progression during service learning: anticipation, familiarization, and commitment. The duration of each phase seemed to be unique to each student. Establishing and developing relationships were perceived as the most meaningful experience while communication and effective teaching strategies were most challenging. Critical reflection ensures that students advance from anticipation and familiarization to commitment, which constitutes change, not only in attitude and understanding, but in behaviour.