The coronavirus disease (COVID-19) pandemic impacted the educational system. Teachers faced significant challenges adapting to online teaching and digitalisation that happened rapidly during the pandemic. With this research we aimed to analyse teachers' role in transformation in online teaching during the COVID-19 pandemic. We adopted a qualitative research method where the sample was selected using the purposive sampling technique. Data were collected through interviews, learning documents, and observations. Data were analysed in 6 stages: preparing and organising data, exploring and coding the data, building descriptions and themes, representing findings, interpreting findings, and validating the results obtained. The results revealed that the teachers performed as technologists, designers, and facilitators during the COVID-19 pandemic. These roles demonstrate the complexity of a teacher's role in online teaching. We provide information on change and teachers' roles in transformation in response to the pandemic. The results of this study are expected to provide information and contribute to policymakers' increasing teacher competence for sustainable education development. These results are expected to provide information and contribute to policymakers' increasing teacher competence as technologists for sustainable education development.