The beginning years of a teacher's career are among the most challenging and complex. Content-specific induction programmes can help teachers navigate these early years of teaching and build their instructional practices. Although there is growing interest in studying new teachers' reform-based instruction, little is known about new science teachers' implementation of science process skills, inquiry, and problem-based learning (PBL). The purpose of this study was to understand how participation in a two-year induction programme influenced the extent of science process skills, inquiry, and PBL new science teachers enacted in their classrooms. This mixed-methods randomised controlled trial (RCT) included three cohorts of treatment teachers (n = 77) and control teachers (n = 52). Data sources included three observation cycles each consisting of 7 lesson descriptions and a videotaped observation each year for two years. Results indicated that more treatment than control teachers incorporated process skills in year one and inquiry and PBL in year two. Both treatment and control teachers implemented process skills and structured inquiry more often than other types of inquiry and PBL. These results underscore the importance of sustained support during the induction years so new teachers can enact inquiry-based lessons that are student-centred and coherent.