Children's early engagement in design of outdoor spaces can form the basis of later attitudes and responsible action for sustainability. The present study is part of a participatory action research project in an urban multi-ethnic preschool in Sweden, involving children, parents, preschool staff and management with a focus on improving the preschool playground. The methodology involved children taking pictures of the outdoor space, informal participant observation by one researcher and conversations with children and teachers. Analyses completed of selected fieldwork excerpts focus on learning opportunities for children and adults, children’s participation, cooperation and leadership for sustainability. Deeper awareness and confidence, and practical pedagogies for staff in preschools are required for effective sustainability education. A joint frame of reference on pedagogical practices and processes for reflection is needed within and across early childhood institutions. More continuous training of staff and preschool leadership would be of benefit. However, such commitment is ultimately a matter of policy to invest in giving preschools the means to develop and realise ambitions for environmental and sustainability education.