Practicum experiences in schools are highly valued in science teacher education programs. Yet, there are few studies examining secondary preservice science teachers' practicum classrooms. This mixed-methods study explored secondary preservice science teachers' perceptions of their practicum classroom learning environments, interpreted from an open-ended survey questionnaire, as well as from an adapted version of the Constructivist Learning Environment Survey (CLES; Taylor, Fraser, & Fisher, 1997). Twenty-two preservice teachers within secondary science methods courses volunteered to complete the survey. Qualitative survey findings were corroborated by quantitative results from the CLES survey. Overall, the preservice teachers perceived their practicum classrooms to incorporate some constructivist learning environment factors, but the critical constructivist perspective underpinning the survey was not found. Additionally, innovative practices cogent with these practices were not supported by most of their co-operating teachers. Implications of how preservice education programs can better support prospective science teachers' views and practices during practicum are discussed. (Contains 2 tables.)