Adolescence and the journey to adulthood involves exciting opportunities as well as psychosocial stress for young people growing up. These normal experiences are potentially magnified for teenagers living with chronic illness or disability and their families. Advances in care have improved survival for children with a variety of serious chronic medical conditions such that many who may once have died in childhood now survive well into adulthood with ongoing morbidity. For those with highly complex needs, care is often provided at major paediatric hospitals with expertise, specially trained personnel, and resources to support young people and their families for the first decades of life. At the end of adolescence, however, it is generally appropriate and necessary for young adults and their caregivers to transition to the care of clinicians trained in the care of adults at general hospitals. While there are some well-managed models to support this journey of transition, these are often specific to certain conditions and usually do not involve intensive care. Many patients may encounter considerable challenges during this period. Difficulties may include the loss of established therapeutic relationships, a perception of austerity and reduced amenity in facilities oriented to caring for adult patients, and care by clinicians with less experience with more common paediatric conditions. In addition, there is a risk of potential conflict between clinicians and families regarding goals of care in the event of a critical illness when it occurs in a young adult with major disability and long-term health issues. These challenges present genuine opportunities to better understand the transition from paediatric to adult-based care and to improve processes that assist clinicians who support patients and families as they shift between healthcare settings.