Following the European recommendations on sustainable educational skills, a strong need has emerged to provide judo coaches with solid and updated knowledge, competences, and attitudes to train older judo practitioners (≥65 years old). This study illustrates the participatory research methodology used to develop and validate the content of the “Educating Judo Coaches for Older practitioners” (EdJCO) online educational programme. From seven countries, 22 judo and sport science experts of the EdJCO team engaged in a four-phase iterative process: (i) a systematic literature review; (ii) seven national focus groups involving 88 experts and an online survey involving 470 judo coaches; (iii) the online EDJCO programme development; and iv) the educational programme evaluation engaging 51 judo coaches as potential end-users. The EdJCO programme encompasses six modules on organization, aging, safety, physiology, psychology, and coaching methodology. Despite the overall positive evaluations, the experts were required to streamline the online programme to meet the coaches’ demands, and to provide a comprehensive handbook to further deepen their knowledge. The cooperation among university scholars, experts from the International Judo Federation Academy, national-level sports clubs, and the judo coaches of older practitioners of different backgrounds and nationalities built a sustainable educational programme suitable for end-users to boost their teaching and training potential across their lifespan.