In UNESCO's recent publication "Education for Sustainable Development: A Roadmap" the idea of community is described as playing an important role in the organization of education for sustainable development as a means of supporting transformations towards sustainability. In the present study we examine the relationship between community and the organization of Early Childhood Education and Care for Sustainability (ECECfS). This examination is based on case studies of Swedish preschool teachers' perspectives and practices in relation to ECECfS. Drawing on Cultural Historical Activity Theory and the concept of ontological Communities of Learners, we describe ways in which community-based characteristics of the preschools shape and are shaped by cultural tools used to pursue ECECfS. Themed-Project Work (TPW), a common means in Swedish preschools of organizing day-today activities, emerged as an important practice through which to examine questions of community within and across preschools. We describe organizational tensions concerning how pedagogical practices like TPW change from being tools to support a preschool's activities, to being objects toward which these activities are oriented. Such changes can enable or constrain a preschool's possibilities for building pluralistic and democratic ECEC environments. We also discuss how the said organizational tensions are rooted in how community is conceived of in preschool provision. Community is constituted not only through the relationships among members of individual preschools but also through the relationships that preschools have with other preschools in their administrative networks. We discuss contradictions that emerge in this matrix of relationships that shape how preschools enact good governance in the pursuit of ECECfS.