In this paper, we investigate the use of CAS in Danish upper secondary school from a norms perspective. The construct of sociomathematical norms is used to understand the potential influence that CAS may have on the rules (and values) in the mathematics classroom. We focus on a situation of teacher change, where the different teachers enact different norm sets related to students’ CAS use in their mathematical work. We zoom in on one student’s perception of this, and find that the teachers’ CAS policies have a direct influence on how students’ navigate in their mathematical work. In particular, the alignment between teachers’ endorsed and enacted norms as well as the extent to which the norms impose judgement on the students’ behalf in relation to CAS use play a major role in this respect.