The past two decades have seen a rise in citizen science projects and tools available for formal and informal learning; however, research has indicated there is a dearth of professional development for educators regarding understanding, adapting, and applying these resources in their learning environments. To address this gap, we created the online "Learning Through Citizen Science" course. The course modules first seek to foster formal and informal educators' identities as citizen scientists then scaffold applying citizen science into their learning environments. To understand participants' preparedness, identities as citizen scientists, and citizen science meaning-making, we collected data through course surveys and participant-generated course assignment artifacts from 599 total participants across 6 continents over a 12-month pilot period. The data were analyzed through thematic analysis, frequency analysis, and descriptive statistics. Our findings suggest that as participants learned about and applied the work of citizen science through the course, they began to develop expansive ways to integrate citizen science mindsets and competencies within their instruction. This study contributes to the small body of citizen science professional development scholarship and offers insight into the efficacy of online trainings that are globally situated and operate at the complex intersections of educator identity and instruction.