The purpose of this article is to report on a study exploring the sustainability work (i.e., practices and pedagogies related to sustainability education) of Finnish early childhood education and care (ECEC) teaching practice settings. Recently, the early years and ECEC have gained increasing attention in sustainability education matters. Educational policy for ECEC has been developed through legislation and renewed curricula for the early years. Research on how sustainability is implemented in ECEC settings as well as in Finnish teacher education is still sparse, but indicates there is a policy-practice gap. The study was conducted in collaboration with municipal ECEC teams (n=34) in teaching practice settings (n=11) in the Helsinki metropolitan area. Data was collected using the "Assessment Tool for Promoting Sustainability in ECEC" (PROSUS) by Furu & Valkonen (2020). The results show that there is great variability in terms of extent and depth in how sustainability work is carried out by the settings. In general, social-cultural issues are addressed at greater depth than ecological and economic issues. The study implies that there is a need to intensify professional development activities that support the capacities for sustainability work in ECEC teaching practice settings in order for teacher education to be effective in the realm of sustainability.