Growing up with a chronic disease can take its toll on children and their families, and if poorly managed, be disruptive to children's long-term health and wellbeing. While parents and health service providers do play a central role in disease management, children's own self-care practices often go unnoticed. In existing literature, children's self-care practices only tend to emerge in research with adolescents who “transition” from pediatric to adult clinical care services. This study was conducted in December 2017 to May 2018 and explores ethnographically the self-care practices of children affected by hemophilia or juvenile idiopathic arthritis in Denmark, with a particular interest in how social relations and material context affect their pre-transition self-care practices. A total number of 16 children and adolescents aged 7–17 years and 39 family members participated in the study. We find that the children participate in three socio-material self-care practices. Firstly, the children actively engage in home treatment of their bodies by changing the setup of medical equipment and incorporating everyday materialities to make treatment more comfortable. Secondly, they play games imitating their own treatment, using medical equipment on dolls or teddy bears to seek out experience and learning. Thirdly, they seek a sense of normality by tactically hiding material signifiers of their disease in online and offline encounters with peers. Our findings suggest that children living with a chronic disease establish and participate in a range of different self-care practices, and actively mobilize people and things around them to achieve precisely this. We conclude that these socio-material self-care practices are central to helping children make sense of living with chronic disease, both to maintain health and wellbeing, but also to gain greater independence. We encourage others to recognize children's pre-transition self-care practices, and the implications of these agentic capabilities.