This study aims to investigate the psychosocial impact of the COVID-19 pandemic on adolescents with type-1-diabetes (T1D). We conducted 18 semi-structured interviews including adolescents with T1D (n = 10, 50% female, 15-18 years) and their parents (n = 8, 88% mothers). The main topics addressed were experiences during confinement regarding everyday life, lifestyle behaviors, diabetes management and treatment. We applied thematic analysis to identify common patterns of meanings. Being aware of belonging to a potential COVID-19 risk group caused worries especially in parents which resulted in strict adherence to preventive measures. Information from trustworthy sources regarding the actual risk mitigated the concerns. Digital diabetes treatment was well accepted and experienced as highly usable. The pandemic situation either facilitated or hindered the transition from parental control to diabetes self-management. While some patients managed to improve healthy lifestyle behaviors as their everyday lives seemed more predictable, others had difficulties in adapting to changed daily routines resulting in increased sedentary behavior and snacking. The perceived level of stress was directly associated with blood glucose levels. In conclusion, the implementation of psychological interventions (both for adolescents with T1D and their parents) addressing mental health literacy and media literacy seems to be important to promote positive coping skills for dealing with the pandemic situation.