Being able to express and address strengths and needs related to health is an important asset to enhance resilience during emerging adulthood. Towards this end, we aimed to develop a specific version of the My Positive Health (MPH) dialogue tool for this developmental period (ages 16-25). By adopting a broad perspective on health and striving for applicability in various settings, this tool ultimately seeks to promote integrated collaboration across various domains (healthcare, social care, school). The tool was co-designed with end users, using mixed methods: a descriptive cross-sectional survey questionnaire (N = 118) followed by qualitative focus groups and interview sessions (N = 36). Participants were Dutch citizens (mean age 21.6; 79% female) who were stratified by educational level and chronic disease status (yes/no). The final selection of the content of the tool was made during expert sessions. A preference appeared for the following dimensions to be part of the dialogue tool: My body, My feelings and thoughts, Meaningfulness, Quality of life, Participation and Daily life. Each dimension was operationalised by aspects (43 in total) to facilitate reflection and dialogue. The following new aspects that are typical for emerging adulthood were formulated and included in the dialogue tool: 'Confidence in yourself', 'Being in control', 'Having confidence in the future', 'Self-expression', 'Meaningful relationships', 'Being able to work or study' and 'Ability to plan'. Other aspects derived from the adult and children's versions of the MPH dialogue tool. A dialogue tool was designed for individuals aged 16-25 in various health- and vulnerability-related conditions and with applicability in various domains. The development of the dialogue tool was specifically driven by the needs expressed by the users themselves. Planned public and patient contribution comprised consultation and collaboration in (i) design, (ii) recruitment, (iii) focus group sessions, (iv) analysis and discussion of the data and (v) dissemination. Not applicable.