In efforts to better prepare students for a technology-driven workforce, many states and districts have pushed for clustered teaching of science, technology, engineering, and mathematics (STEM) in K-12 schools, yet science and mathematics remain the cornerstones upon which broader opportunities in STEM education are built. Teachers serve as boundary spanners--connecting knowledge, experiences, and opportunities for access--and for that reason, we focus on teachers as the most promising change agents in science and mathematics education in urban schools. This qualitative study explores the potential for both initial preparation and continued development of practicing teachers to occur simultaneously through a co-learning university-school-community partnership model, summer residency, and coursework, using critical and culturally relevant outdoor experiential learning. Findings suggest that there was a clear shift with practicing teachers to be more open-minded about both the effectiveness and applicability of experiential outdoor learning in urban spaces, and the richness of urban schools and spaces themselves. Future Teachers were able to incorporate critical and culturally relevant experiential learning into their coursework and master's project, and engage with their students and mentors in meaningful ways. The article suggests pathways for partnership development and implications for urban education classrooms.