To raise Earth Science (ES) interest in pre- and in-service K-12 teachers, we incorporated ES into an environmental education (EE) course for this audience. The approach recognizes the growing interest in EE, and the focus on inquiry and student-centered learning in British Columbia schools. This case study examines the impact of this innovation on participant attitudes to and interest in ES, and their confidence to teach ES in their own (future and present) K-12 classrooms. Earth science was incorporated into three of six modules of EDU452 Environmental Education at Simon Fraser University. We ran two pilots with 52 participants in summer 2018 and 2019. Research methods included field observations, student interviews, final portfolios, and a pre- and post-course survey. We found that incorporating ES, while increasing student interest in ES and raising awareness of relevance of ES to our lives, did not result in a similar high confidence level to teach ES. Students acknowledged that further ES instruction would be needed. Students recommended that ES be incorporated into all the course modules in the future. Constructivist and place-based learning were widely accepted by participants for offering personal ownership of learning, engaging experiences, and learning relevant to local settings and issues. Inquiry learning was reported to promote student interest in and enjoyment of ES. Careful design of leading questions and guidance during the inquiry process to accommodate individual's prior exposure to ES and conceptual difficulty of ES topics are recommended.