This study explored the ways in which pre-service teachers' (PSTs) understanding of the nature of science (NOS) emerged in their experience of a socio-scientific inquiry-based (SSI) experience. In this study, an undergraduate science course with structured collaboration on a SSI-based inquiry between PSTs and campus scientists was intertwined with their changing conceptions of NOS. Qualitative and quantitative data were collected and progressively analyzed to illuminate changes in twenty-four PSTs' understanding of the nature of science throughout the experience. Results indicated that that PSTs experienced substantial growth in the targeted understandings of NOS. However, findings also revealed some aspects of NOS for which several of the PSTs continued to hold uninformed conceptions. Insights from this study that add to the on-going discussions about the relationship of SSI and NOS include 1) the importance of inquiry and 2) NOS understanding as linked to PSTs perception of inclusion in the process of SSI investigations.