This case study involved an urban elementary school's implementation of a peer-observation professional learning protocol, collegial visits (CVs). The study sought teachers' perceptions of CVs as a professional learning format, whether CVs aligned with contemporary professional learning expectations, how and in what ways CVs influenced social capital and what conditions enhanced or detracted from the implementation of collegial visits. Data included interviews with 13 educators (9 teachers; 4 leaders), implementation artefacts and rubric scores from leadership walkthroughs. Results indicated that CVs, supported by enhancing conditions and resisted by many fewer detracting conditions, positively impacted instruction. Teachers perceived CVs positively, and CVs aligned strongly with standards. CVs increased social capital by improving instructional practices across the school's classrooms (at scale), increasing collective ownership and helping teachers to view colleagues as resources.