IntroductionDischarge communication is an important aspect of patient care but frequently has shortcomings in emergency departments (EDs). In a paediatric context, youth or parents with young children often leave the ED with minimal opportunity to ask questions or to ensure comprehension of important information. Strategies for improving discharge communication have primarily targeted patients and/or parents, although neither group has been engaged in intervention design or implementation. Furthermore, ED healthcare providers (HCPs), important actors in discharge communication practice, are rarely consulted regarding intervention design decisions. We will generate evidence to enhance discharge communication by engaging youth, parents and HCPs in the codesign of ED discharge communication strategies (EDUCATE) for asthma and minor head injury.Methods and analysisThis mixed methods study will take place at two academic paediatric EDs in Canada. The study will occur in two phases: (A) codesign and refinement of the intervention prototypes; and (B) usability testing of the prototypes. During the first phase, two codesign teams (one for each condition) will follow a series of structured design meetings based on the Behavior Change Wheel to develop the EDUCATE interventions. Each codesign team (composed of youth, parents, HCPs and study researchers) will collaborate to identify priority target behaviours and acceptable components to include in the interventions. During the second phase, we will conduct usability testing in two EDs with a group of youth, parents and HCPs to refine the interventions. Two cycles of usability testing will be conducted with intervention refinement occurring at the end of each cycle.Ethics and disseminationInformed consent will be obtained from all participants. Ethics approval for this study has been obtained from the Research Ethics Board, IWK Health Centre. Results from this study will form the basis of a future effectiveness implementation trial. Key findings will be presented at national and international conferences and published within peer-reviewed journals.