Nursing education relies on nurses to supervise students in practical skill learning during their clinical placement periods, yet literature is sparse regarding what this supervision actually entails. The study aimed to explore the learning actions that characterised nurses' and students' interaction during supervision of peripheral vein cannulation attempts on patients in hospital, and how these learning actions influenced the students' practise. In this study, 38 video-recorded attempts of the practical skill peripheral vein cannulation conducted of nine nursing students were analysed. Of the 38 attempts, 10 were successful. In successful and failed attempts both, students and nurses primarily engaged in learning actions that informed, reminded, or corrected the students; students and nurses rarely engaged in learning actions characterised by reflection and discussion. A surface approach to learning was insufficient for most students to successfully insert a vein cannula during their clinical placement.