ObjectiveDeveloping and evaluating effective transition interventions for young people (16–25 years) with inflammatory bowel disease (IBD) is a high priority. While transition clinics (TCs) have been recommended, little is known about their operating structures and outcomes. This study aimed to gain insight into the value of a TC compared with direct handover care.DesignControlled mixed-methods evaluation of process outcomes, clinical outcomes and patient-reported outcomes.SettingTwo outpatient IBD clinics in the Netherlands.ParticipantsData collection included: semistructured interviews with professionals (n=8), observations during consultations with young people (5×4 hours), medical chart reviews of patients transferred 2 to 4 years prior to data collection (n=56 in TC group; n=54 in control group) and patient questionnaires (n=14 in TC group; n=19 in control group).OutcomesData were collected on service structures and daily routines of the TC, experienced barriers, facilitators and benefits, healthcare use, clinical outcomes, self-management outcomes and experiences and satisfaction of young people with IBD.ResultsAt the TC, multidisciplinary team meetings and alignment of care between paediatric and adult care providers were standard practice. Non-medical topics received more attention during consultations with young people at the TC. Barriers experienced by professionals were time restrictions, planning difficulties, limited involvement of adult care providers and insufficient financial coverage. Facilitators experienced were high professional motivation and a high case load. Over the year before transfer, young people at the TC had more planned consultations (p=0.015, Cohen’s d=0.47). They showed a positive trend in better transfer experiences and more satisfaction. Those in direct handover care more often experienced a relapse before transfer (p=0.003) and had more missed consultations (p=0.034, Cohen’s d=−0.43) after transfer.ConclusionA TC offer opportunities to improve transitional care, but organisational and financial barriers need to be addressed before guidelines and consensus statements in healthcare policy and daily practice can be effectively implemented.