In place of generalist delivery, externally provided physical activity programmes (EPPAPs) are potentially an effective method for offering primary school students specialist physical education (PE) instruction, as well as providing training for generalist classroom teachers. In the present study, a group of generalist teachers were interviewed regarding the professional benefits of their class's involvement in a 6-month EPPAP. Semi-structured interviews were conducted with five generalist teachers pre- and post-intervention. Wilcoxon signed ranks procedures revealed moderate to large effect sizes for improvements in teachers' beliefs about their ability to provide students with a range of PE-based requirements from pre- to post-intervention (e.g., inclusivity, fun, safety). Content analyses also revealed that generalist teachers reported improvements in their skills, knowledge, and confidence as a result of observing and working alongside PE specialists. This investigation provided preliminary evidence that generalist teachers who observe and participate in an EPPAP report enhanced confidence and skills regarding their ability to effectively instruct PE. (Contains 2 tables.)