BackgroundAn increase in self-management skills for adolescent thoracic transplant recipients may improve health outcomes and facilitate a successful transition to adulthood. The iPeer2Peer© program is an online peer mentorship program that has been successfully implemented as a self-management intervention in multiple chronic disease populations. This study aimed to determine the implementation and effectiveness outcomes of the iPeer2Peer program for adolescent thoracic transplant recipients. MethodsA type III, hybrid implementation-effectiveness pilot study that comprised a quasi-experimental single-arm pre-post design was used to evaluate the iPeer2Peer program. Participant mentees, ages 12 to 17, were recruited from two large Canadian transplant centres. Peer mentors, ages 18 to 25, were thoracic transplant recipients who had successfully transitioned to adult care and self-manage their condition. A mixed methods approach for data collection was used, including interviews, focus groups, and standardized questionnaires. ResultsTwenty mentees (median 15.0 years, IQR 3.3 years; 65% female) completed the iPeer2Peer program with nine young adult mentors (median 21.0 years, IQR 3.0 years; 78% female). Implementation outcomes indicated that the iPeer2Peer intervention was perceived as feasible, adoptable, acceptable, and appropriate for adolescent thoracic transplant recipients. Significant findings were noted in mentees for increased self-management and a decrease in overall depression and anxiety symptoms. ConclusionsThe successful implementation of the pilot iPeer2Peer program offers support to evaluate the scalability, sustainability, and cost-effectiveness of the program for adolescents with chronic illness, specifically thoracic transplant recipients. Changes to the iPeer2Peer program that facilitate a flexible delivery may help implementation and acceptance.