After posterior fossa tumour surgery, up to 39% of children experience postoperative cerebellar mutism syndrome (CMS) characterized by mutism and other motor and cognitive impairments. There is a lack of knowledge on the patient-reported challenges and long-term needs. Consequently, no specific recommendations exist for rehabilitative and supportive interventions for patients with CMS. The aims of this study were to explore the patients' experiences related to the sequelae of CMS, to identify challenges and needs regarding support and rehabilitation in the period of growing from child to adult and to add perspectives for future developments of supportive care and rehabilitative guidelines. Ten semi-structured interviews were conducted with young adults diagnosed with CMS as children. A thematic analysis identified four themes describing challenges impacting aspects of the participants' lives. Four main themes were identified and highlight the rehabilitative need for focus on verbal and non-verbal communication skills in addition to the physical impairments. We found that brain tumour survivors with CMS can benefit from social and educational rehabilitation, straightforward and truthful information, support in structuring their everyday lives and increased public knowledge of CMS. Children with CMS face a variety of challenges affecting many aspects of their everyday lives. They should be entitled to the elements of a current rehabilitation initiative for childhood cancer to support patients' social disability and educational decline. Finally, we identified a need for an official information publication.