Background: The paper focuses on the continuous professional development of sports coaches, and the role of informal education and coach developers. Special attention is devoted here to the coach training and development system in Poland. The paper aims to indicate the need for strong support for both informal coach education and the important role of coach developers in professional coach development in Poland and worldwide. Methods: We performed an analysis of secondary data on the system of sports training and continued professional development in Poland. Primary research data on Polish Olympic and Paralympic national team coaches (13 sports), their qualifications, competencies, and views on their continued professional development were also used. The study covered 103 coaches in Olympic or Paralympic sports. The national team coaches surveyed also conducted a self-assessment of their professional development needs, opportunities, and challenges. The method of balance of competencies based on data documenting the stock of knowledge, experience, and social competencies acquired in the learning process of the surveyed coaches was applied. Results: It was found that after completing their formal education, the coaches declared participation in various types of continuous professional development courses and training, while the most valued forms of continued professional development included informal learning, and sharing experiences and good practices with other coaches. Conclusions: The data supports the need to educate more sport coach developers and introduce them to the professional coach development system to guide coaches and facilitate their knowledge and competence acquisition.