ObjectivesTo determine whether a multicomponent sun protection intervention programme (mHealth) for young organ transplant recipients (OTR) leads to a higher increase of preventive knowledge and behavioural change than an e-learning education programme (eHealth).DesignRandomised controlled trial with one preintervention baseline survey and three follow-up surveys after 6 weeks, 6 and 12 months. Comparison of two different intervention schedules with a control group (CG).SettingMulticomponent sun protection trainings in Germany, the Netherlands and Austria between June 2013 and September 2015.Participants137 OTRs (5–22 years of age, 61 females/76 males) participated in the study.Interventions(A) Intervention group 1 (IG1): personal training with subsequent forwarding of individual ultraviolet index-dependent sun protection recommendations via short message service (SMS); (B) intervention group 2 (IG2): e-learning training without SMS; (C) CG: regular information letters, online training after 1 year.Outcome measuresKey questions were used to form a knowledge and a behavioural score. Behavioural strategies and knowledge were quantified through self-administered questionnaires.ResultsAnalyses 6 weeks after the intervention showed a higher knowledge increase in both IG compared with the CG (IG1 to CG: OR 12.64, 95% CI 4.20 to 38.20; IG2 to CG: OR 2.59, 95% CI 0.95 to 7.04). Sun protection behaviour improved slightly but not significantly in both IG (IG1 to CG: OR 2.56, 95% CI 0.93 to 7.00; IG2 to CG: OR 1.22, 95% CI 0.45 to 3.32). One year after the intervention, no behavioural changes were observed in either IG compared with the CG. IG1 but not IG2 still scored significantly higher in sun protection knowledge than the CG 1 year after intervention (IG1 to CG: OR 4.46, 95% CI 1.48 to 13.43; IG2 to CG: OR 1.41, 95% CI 0.51 to 3.93).ConclusionsThis multicomponent sun protection programme provides a promising strategy to increase sun protection knowledge and possibly also protective behaviour in young OTR.Trial registration numberDRKS00011393.