Introduction The majority of childhood, adolescent and young adult (AYA) cancer survivors suffer from long-term and late effects such as fatigue, psychological distress or comorbid diseases. Effective health promotion strategies are needed to support the health of this vulnerable group. This protocol provides a methodological description of a study that aims to examine the feasibility and safety of performing a randomised clinical trial (RCT) on a wilderness programme that is developed to support the health of AYA cancer survivors.Methods and analysis The pilot RCT study has a mixedmethod design, including quantitative and qualitative evaluations. Participants are AYAs, aged 16–39 years, that have been diagnosed with cancer during childhood, adolescence or young adulthood. A total of 40 participants will be randomly assigned to a wilderness programme (n=20) or a holiday programme (n=20). Both arms include participation in an 8-day summer programme, followed by a 4-day programme 3 months later. Primary outcomes are feasibility and safety parameters such as time to recruitment, willingness to be randomised, programme adherence and adverse effects. Secondary outcomes include self-reported health such as self-esteem, quality of life, self-efficacy and lived experiences. Descriptive statistics will be used to analyse outcomes and explore indications of differences between the programmes. Interviews are analysed by directed content analysis and hermeneutic phenomenology. A convergent parallel mixed-method analysis design will be applied to integrate quantitative and qualitative data. Results of this feasibility study will inform the preparation for a larger RCT with AYA cancer survivors.