Curriculum materials are important resources with which teachers make pedagogical decisions about the design of science learning environments. To become well-started beginning elementary teachers capable of engaging their students in inquiry-based science, preservice elementary teachers need to learn to use science curriculum materials effectively. Thus far, few other studies have investigated how preservice elementary teachers adapt science curriculum materials to better reflect five essential features of inquiry-based teaching and learning articulated in contemporary science education reform. Findings from previous research suggest that preservice elementary teachers can productively adapt science curriculum materials to make them more inquiry-based. The mixed-methods study presented here extends these findings by illustrating the essential features of inquiry preservice teachers emphasize in their curricular adaptations and the specific types of adaptations the preservice teachers make. Results suggest that the preservice teachers consistently attended to all five essential features of inquiry in their curricular adaptations. The types of adaptations that they made to promote each of these features of inquiry provide insight into their curriculum design practices and learning about science as inquiry that can serve as important leverage points for teacher education experiences and curriculum materials designed to support elementary teachers' science teaching practice and learning. (Contains 4 tables.)