The current study examined the beliefs, experiences, and challenges of primary school teachers in Vietnam in the first years of implementing a new curriculum. The study was conducted at five primary schools in a big city in Vietnam. The data consist of in-depth semi-structured interviews with eleven teachers. Analysis of qualitative data showed that the teachers held positive views on the new curriculum, commenting that the curriculum had many strengths and was introduced at the right time. The teachers reported that they largely understood the principles of and made attempts to realise the new curriculum. They highlighted several initial positive effects of the curriculum on students and themselves. However, the teachers also faced several challenges, especially the negative impact of the COVID-19 pandemic which forced them to transition to online teaching. In addition, the teachers showed some difficulties in designing the long-term syllabus and the objectives for individual lessons due to the fundamental differences between the previous curriculum and the new one. Implications for teachers and policymakers for Vietnamese primary education, and possibly similar contexts, are discussed.