Teacher practices are essential for supporting learners in scientific inquiry practices of framing research questions, designing and conducting investigations, collecting data, and drawing conclusions. This study examines instructional practices of two Grade 11 Physical Science teachers engaged in teaching practical investigations. Data were collected from video recordings of teachers' enactment of pre-laboratory, laboratory and post-laboratory practical investigation lessons. Other data sources included video-based classroom observations, teacher and learner interviews, and artefacts, such as teacher handouts, supplemental materials and learner work. The results suggest that when teachers introduce practical investigations, they vary in the practices they engage in as well as the quality of their use of these practices. Implications for teacher practices of scientific inquiry are explored.