ObjectiveTo develop supportive interventions for adults with new-onset type 1 diabetes (T1D) to facilitate positive adaptive strategies during their transition into a life with diabetes.DesignThe study used a co-design approach informed by Design Thinking to stimulate participants’ reflections on their experiences of current care and generate ideas for new supportive interventions. Visual illustrations were used to depict support needs and challenges. Initial discussions of these needs and challenges were facilitated by researchers and people with diabetes in workshops. Data comprising transcribed audio recordings of the workshop discussions and materials generated during the workshops were analysed thematically.SettingsSpecialised diabetes centres in Denmark and the United Kingdom.ParticipantsAdults with new-onset T1D (n=24) and healthcare professionals (HCPs) (n=56) participated in six parallel workshops followed by four joint workshops with adults (n=29) and HCPs (n=24) together.ResultsThe common solution prioritised by both adults with new-onset T1D and HCP participants was the development of an integrated model of care addressing the psychological and social elements of the diagnosis, alongside information on diabetes self-management. Participants also indicated a need to develop the organisation, provision and content of care, along with the skills HCPs need to optimally deliver that care. The co-designed interventions included three visual conversation tools that could be used flexibly in the care of adults with new-onset T1D to support physical, psychological and social adaptation to T1D.ConclusionThis co-design study has identified the care priorities for adults who develop T1D, along with some practical conversational tools that may help guide HCPs in attending to the disruptive experience of the diagnosis and support adults in adjusting into a life with diabetes.