Peer placements, pairing two preservice teachers with a cooperating teacher, have been shown to provide a more supportive and collaborative context for learning to teach than the traditional student-cooperating teacher, single placement model. In some cases, however, tensions existed. This qualitative study seeks to expand the extant research by identifying and analyzing the challenges 24 preservice teachers experienced in their peer placements. While virtually all preservice teachers viewed their peer placements positively, results indicate that all preservice teachers negotiated challenges that pertained to the act or perceived value of collaboration in practice. Specifically, preservice teachers' prior experiences had not prepared them for in-depth collaboration, and their tendency to view teaching as an autonomous profession that one gains entry into by "sinking or swimming" influenced their perception of the role of collaboration in professional learning. Recommendations are provided to guide the development or refinement of peer placements.