This study examined pre-service primary teachers' (PPTs) initial NOSI conceptions and their evolution after the immersion in a specific teaching module focused on inquiry and NOSI. The participants were 40 PPTs attending a science education course during a semester. The study consisted of a pre-test/post-test design approach framed qualitative methods. The intervention consisted of nine 90-minute sessions in which participants addressed NOS and NOSI aspects through explicit-reflective teaching combined with the implementation of inquiry tasks set in everyday-life contexts. Data were collected through an open-ended questionnaire both at the beginning and at the end of the module and they were examined through content analysis. The main findings suggest that pre-service teachers presented naive NOSI conceptions when entered the course, and their ideas improved considerably in most of the NOSI aspects after their immersion in the teaching module.