This study explores how teachers' communities of practice facilitated the transition to emergency remote teaching after school closures in South Korea during the coronavirus disease 2019 (COVID-19) pandemic. We also investigate whether and how teachers' online education experiences in times of crisis continue to influence face-to-face teaching practices. We first conducted a literature review on teachers building communities of practice to cope with the pandemic and their execution of emergency remote teaching with collective professionalism. Five experienced teachers from elementary and middle schools participated in a semi-structured interview to share their experiences since the outbreak of COVID-19 until Spring 2022. We found that in response to significant pandemic-related challenges, teachers rapidly adapted to the digital educational environment, with assistance from their peers, through online and offline learning communities. Moreover, teachers' online education experiences have contributed to innovative teaching practices with technological integration. We present the implications for teacher education research and practice in the post-COVID-19 era.