This article advocates the use of free play in the provision of the Social and Emotional Aspects of Learning (SEAL) programme in schools. It uses case studies to illustrate how children develop and use the five strands of SEAL while playing. The author draws on recent research and literature to support the idea that SEAL skills are caught rather than taught; and that play is the medium most able to provide opportunities for becoming more self-aware, empathic and motivated as well as becoming more able to manage feelings and develop and deploy social skills. The need for school staff to be supported in providing free play and in facilitating social and emotional development in new ways is also considered. The essential role of the adult in developing relationships that support the development of SEAL skills is acknowledged.