Research into the experiences of casual relief teachers (CRTs) (substitute or supply teachers) across Australia and internationally has reported feelings of marginalisation among participants. These findings are concerning when one considers that students might be in the care of CRTs for an equivalent of 1 year or more throughout their schooling. When CRTs describe such feelings there is a suggestion that they do not feel a part of the community of practice in which they work. Accordingly, their opportunities for professional learning are often compromised, which has implications for their ability to maintain pedagogical knowledge and skills. This study used cluster sampling survey data to offer insights into professional challenges faced by CRTs. The discussion examines the self-determined skills of 59 Australian CRTs and the way schooling is organised that may leave them feeling excluded rather than members of what should be their "communities of practice."