<p>Cybersecurity is rarely taught in formal elementary education due to the lack of standards and existing curricula. To address this gap, we developed a cybersecurity and cryptology curriculum for informal learning environments, accompanied by an asynchronous Online Professional Development (OPD) program. This study examines the design strategies of the OPD to support afterschool educators in teaching this critical topic. We explored the experiences of six afterschool educators, focusing on their perceived preparedness to implement the curriculum and their use of the OPD. The results revealed that teachers employed different approaches to use the OPD, highlighting its flexibility to fit into the educators’ tight schedule and the critical role of instructional videos and implementation guides in bridging educators’ content knowledge. Reported challenges, including curriculum structure and technology use, highlight the need for improved support to enhance educators’ technological and pedagogical knowledge. This study contributes to the ongoing discussion about enhancing STEM education in informal settings by showcasing the potential of asynchronous OPD in helping educators engage elementary students in learning cybersecurity and cryptology.</p>