This manuscript reports the results of a research study exploring the ways in which physical space and teacher pedagogy are related to preschoolers’ engagement with science and engineering practices while at play. Using the Science and Engineering Practices Observation Protocol (SciEPOP), researchers captured children’s engagement with the eight science and engineering practices identified in the Next Generation Science Standards (NGSS). This study explored relationships between specific playspaces, materials, and pedagogical strategies, and children’s patterns of engagement with particular science and engineering practices during free play. There are notable differences in the spaces, materials, and pedagogies children encounter across the four participating preschools, and these differences suggest significant gaps in children’s opportunities to engage in and deepen their enactment of science and engineering practices. The authors present evidence in support of adaptive, personalized strategies for deepening children’s engagement with science through play, and rase questions about equity in early science learning environments that have implications both nationally and internationally for science education research, practice, and policy. (author abstract)