This thesis gives a better understanding of informal learning and how it contributes to children's educational development. The current literature in the field has no consensus of a definition of informal learning and tends to polarise informal learning and formal learning. This thesis contributes to new knowledge by giving a better definition of informal learning, demonstrates that children can a learn a lot in a relatively short space of time during informal learning experiences and highlights how informal learning can be blended with formal learning in ways which maximise children's holistic development. A multiple case study approach using both qualitative and quantifiable data is used to find out how and what children learn during informal learning experiences. The three case studies are: `The Eden Project: Learning at an Informal Learning Centre', `Garden's for Life: Gardens as a Learning Environment' and `Survive and Thrive: A forest school experience'. The case studies analyse and synthesise the findings from a number of my own published papers and evaluations to seek out emerging themes. The emerging themes identified and discussed are the interrelationship of children's cognitive, social and affective learning in informal learning contexts; the importance of children's self-esteem, confidence and motivation, in the learning process; the integration of informal and formal learning to maximise children's educational development. The thesis concludes that informal learning is one way to get children intrinsically motivated to learn, it can improve children's self-esteem and confidence which in turn leads to better academic knowledge and understanding. Also, informal learning is often better able to meet the needs of a greater range of children's learning Styles than traditional formal teaching. Further, it is valuable to get children out of the classroom in order to provide them with a wide range of exciting experiences, to create informal learning environments in schools and to firmly establish informal learning into schools' curriculums. Finally, practitioners need to be more conscious of utilising both formal and informal strategies in any given learning context to maximise children's learning. Therefore, this thesis gives a strong lead to a greater understanding of the value of informal learning and how it can be utilised to contribute to children's educational development.