Informal science educators' goals for preschool-age audiences (ages 3-5 years) shape how they design opportunities for children and families to learn science. However, little research has explored the opportunities provided by informal science educators for preschool-age children to engage in science practices. We invited 12 informal science educators across multiple informal science venues (including nature parks, planetaria, and science centers) in the U.S. to be interviewed and observed facilitating programs with a preschool-age audience at their venue. Using thematic analysis, we found that while four out of twelve educators in our study provided opportunities for young children to engage in science practices, the remaining programs provide only intermittent (four educators) or no opportunities (four educators) for young visitors to do science as an active, social engagement with science phenomena in the natural world. The extent to which educators designed and engaged preschool-age children in science practices was reflected in their own beliefs about how young children do science. These findings can help researchers and practitioners develop professional development to support the informal science education community to build capacity towards deepening young visitors' engagement with science as an evidence-based enterprise.