This case study is the first phase of a large-scale design-based research project to implement a theoretically derived double-layered CoP model within real-world teacher development practices. The main goal of this first iteration is to evaluate the courses and test and refine the CoP model for future implementations. This article demonstrates the potential synergies between two major approaches to teacher professional development practices: i) teachers’ CoPs development and ii) online teacher education courses. The analysis of student inservice teachers’ CoPs experiences shows that the two layers of CoPs supported each other iteratively through the course period.