The study reported in this paper was part of a larger study that explored pre-service teachers' perceptions of the effectiveness of a problem-based learning (PBL) teaching approach for developing their mathematics pedagogical content knowledge (PCK) and their ability to enact their PCK in a tertiary mathematics education subject. This paper reports the qualitative semi-structured interviews used to capture the student voice with respect to the impact of the PBL approach used on the development of their mathematics PCK in comparison to their previous experiences with teacher-directed instruction. Overall, responses from the interviews revealed the pre-service teachers considered the PBL method used in this study was a more effective way to learn compared to being taught using a teacher-directed instructional approach, and further, that they will most likely use PBL when they become teachers.