This article presents the findings of an international comparative multiple-case study that examined the sudden change from classroom to remote online teaching during the COVID-19 pandemic. The study specifically explored the experiences of teachers in Northern Finland, England, and Norway, seeking to provide new information about the education situation and identify the focus areas to guide the education of future teachers. The data were collected in three different ways in three different contexts: via an online survey of in-service teachers in Lapland, Finland (N = 164), and through different semi-structured interviews with teachers in England (N = 20) and northern Norway (N = 30). The data analysis was conducted in two phases. The first phase focused on teachers' experiences in teaching and learning and the second phase on teachers' challenges. The results reflect teachers' desire for additional education on online pedagogy, as well as the significance of teacher collaboration and knowledge sharing. The findings can be used to develop pre- and in-service teacher education, supporting the dynamic digitization of teacher education programs and policies. We recommend that strategies should be developed for how such programs can strengthen future teachers' interaction, collaboration, and knowledge sharing.