Stephens (2008) described structural thinking as an awareness of the way different occurrences of a mathematical property develop into correct generalisations. Many primary pre-service teachers (PSTs) graduate from their tertiary studies without the ability to notice structural thinking. In this study, two primary PSTs learned to notice structural thinking in three cycles of professional learning workshops; teaching mathematics; and, interviews. Here, we report on how the PSTs attended to structural thinking in their classroom communication and their awareness of doing so in the workshops and interviews. Results indicate the PSTs improved their noticing of structural thinking.