Abstract Introduction People experiencing mental ill-health have greater disparities in cancer specific morbidity and mortality. Factors influencing cancer prevention include increased risk behaviours and frequent encounters with barriers to health care utilization. The Patient Navigation Model (PNM) has been proven to reduce barriers in accessing cancer preventive care in vulnerable populations. To facilitate successful implementation, the conceptual features of the PNM were co-designed with patients and other relevant stakeholders. Methods Twelve focus groups were conducted in January 2024 at four pilot sites in Austria, Greece, Poland, and Spain. Iterative focus group discussions were carried out following key considerations for the PNM as outlined by DeGroff et al., audio recorded and transcribed verbatim. Transcripts were analysed deductively using a directed content analysis while allowing for potential inductive emergence of codes and topics. A total of 50 participants attended, representing five groups (individuals with mental ill-health, care givers, care team members, representatives of mental health organizations, and representatives of service managers). Results The co-design focus groups allowed for the PNM to be contextually adapted to each pilot site, but similarities in the approach emerged within the following four themes: 1) the requirement for a person-centred approach, 2) consideration of both person-specific and context-specific needs, 3) flexibility and competencies of navigators and 4) variation of navigation services (e.g., improving health literacy, promoting a healthy lifestyle, and providing practical support). Conclusions Participatory approaches in co-designing interventions allow for context specific development of interventions to meet the requirements of people with complex needs. Co-designing the PNM is part of activities of the CO-CAPTAIN project funded by the European Union’s Horizon Europe Programme (GA 101104784). Key messages • The Patient Navigation Model for Primary Cancer Prevention is a tailored intervention aiming to meet the needs of individuals experiencing mental ill-health. • The conceptual features of the Patient Navigation Model for Primary Cancer Prevention were co-designed with patients and other relevant stakeholders.