The content of this book is the findings of a case study undertaken in an early childhood education and care setting in urban Auckland, New Zealand. This study explored the foundational mathematical thinking and behaviour of children aged between 12 months and three years while engaged in unstructured outdoor play experiences. The discussion regarding the findings of the case study shows how very young children (toddlers) explored their outdoor setting in a variety of mathematical ways. These findings are then described in terms of commonly recognised mathematical themes showing toddlers as competent and confident learners in thier outdoor setting.