The European Union's policies on lifelong learning, initiated in the 1990s, have significantly influenced the development of Italy's legislative framework in this area. This paper presents the key findings from a series of collaborative research projects conducted between Roma Tre University and the National Forum of the Third Sector. Undertaken between 2016 and 2023, these participatory studies focused on experiential learning among individuals employed within these organisations, as well as methodologies for competence recognition. The research on experiential learning has elucidated that all human activities can serve as learning opportunities, provided individuals engage in reflective practices to derive meaning from them. Within the contexts of lifelong and lifewide learning, the validation of non-formal and informal learning offers significant benefits for adults, fostering personal, social, civic, and occupational development, while reducing barriers to re-entry into formal education systems. For initiatives within non-profit organisations aimed at facilitating validation processes, a deeper understanding of the competences cultivated through such experiences is essential. The presence of recognised standards is deemed a crucial formal prerequisite for validation. The frameworks emerging from the presented studies demonstrate that activities within the Third Sector primarily promote the development of transferable competences, crucial for both enhancing technical-professional skills and fostering conscientious and proficient conduct in social and civic engagement. In this context, engagement in the Third Sector emerges as a catalyst for nurturing citizenship competences vital for navigating national and international transitions, promoting social cohesion, and advancing democracy. Through the findings of these studies, the Italian Third Sector has played a significant role in shaping public policies concerning lifelong learning and the validation of experientially acquired competences, notably regarding the incorporation of transferable competences into the National Repertoire. Additionally, some lines of action for influencing the implementation of validation policies at the European level will be discussed.