Many pre-service and in-service mathematics teachers have reflected vulnerabilities and unpreparedness for online teaching during the period of the COVID-19 pandemic. They searched for supports and resources to enhance their knowledge, skills, and dispositions relative to online teaching and learning. However, there is no clear path towards reaching these goals. This qualitative and interpretive research focuses on 48 pre-service and in-service teachers’ online teaching and learning experiences; while they were engaged in a semester-long mathematics-method course. The findings of this study suggest that factors, like interactions, communication, and peer support impact the pre-service and the in-service mathematics teachers’ beliefs and practices toward online teaching and learning. The findings also suggest that social and cultural factors, such as knowing and understanding students’ cultural background, access and equity in mathematics education, learners’ social and emotional development, and parents’ involvement influence mathematics teachers’ practices regarding online teaching and learning. The findings indicate that the transformation from in-person to online learning requires the enhancement of pre-service and in-service mathematics teachers’ online preparations, particularly in the areas of technology, pedagogy, communication skills, and classroom management.