It is widely recognised that tertiary education does not provide all of the knowledge and skills required to succeed in modern societies. Personal and interpersonal skills--so-called "soft skills"--are also needed to complement professional skills and expertise, and become an essential part of an individual's personality. One way of acquiring soft skills is volunteering with associations and non-governmental organisations (NGOs). This paper discusses the involvement of French third-level students in voluntary activities and the skills they acquire as a result. The author presents the findings of a study involving a questionnaire and semi-structured interviews. Results show that many students develop skills linked to their future professional career, that they reflect on this consciously and feel enriched by the experience. The author argues that "non-professional" activities like volunteering can be actively incorporated into students' learning process, making their overall experience of higher education more active, enjoyable and relevant. Learning through action was found to be the most important factor in the acquisition of soft skills. This article aims to contribute to research on the educational dimension of volunteering, demonstrating that it benefits both personal and professional development.