The field of environmental education (EE) strives to develop innovative practices to address emergent issues such as equity, climate change, and urbanization. Through facilitating workshops and ongoing networks for the exchange of ideas, professional development programs may foster innovation or practice change among environmental educators. This study investigates change in practice among environmental educators who participated in one of three online and face-to-face professional development programs. Drawing from practice theory, we measured elements of EE practice including goals, audiences, settings, activities, resources, and ideas. The results showed that across all three programs participants incorporated new resources and ideas into their practices whereas changes in other practice elements varied among programs. Participants in all three programs produced eBooks or ongoing networks that can be used as indicators of practice innovation. This study suggests that practice theory can be used to inform studies of professional development outcomes and examine EE practice, but that practice innovations may be more readily measured at the group rather than individual level.