This chapter underlines the importance of exploring themes and topics of/for ESD in early years. It presents an overview of a practical project, the Bat Conservation Project, and how it has been implemented with young children in England and in Kenya. The project is connected to the areas of Learning and Development of the EYFS (Early Years Foundation Stage) and provides the basis for a professional development resource for early years teachers. This project offers an example of how cross-curricular activities and experiential learning can be used to engage young children with more complex and simpler environmental topics in ESD/GC.