Language teachers can uncover new understanding of the teaching and learning process through reflecting on critical incidents [Richard, J.C., and T.S.C. Farrell. 2005. "Professional Development for Language Teachers." New York, NY: Cambridge University Press]. Based on the data analysis of workshop handouts, observation notes, and interviews, this study analyses three critical incident workshops designed and delivered to 19 elementary school English teachers in Taiwan in terms of design, participants' learning, strengths, and suggestions. The study has the following findings. First, the participants moved from knowing nothing about critical incidents or mazes to writing up, discussing, and analysing critical incidents in collaborative reflective practice. Most importantly, the workshop facilitator fostered a safe and trusting environment for participating teachers to discuss critical incidents freely and combat their isolation. Five elements are recommended to be integrated into the design and delivery of critical incident workshops.