Research demonstrates that content, language, and literacy integration is challenging for teachers working in content-based instructional contexts such as immersion and Content and Language Integrated Learning. Although teacher preparation programs for content-based instruction contexts exist, it is unclear whether and how they help pre-/in-service teachers acquire the knowledge and awareness they need to be effective. In recent years, scholars have lamented that research has ignored immersion teacher education and that teachers and teacher educators do not yet fully understand the knowledge base that immersion teachers require. This article reports on an exploratory study that included an examination of web-based program descriptions, course outlines, focus groups with course instructors (N = 11), and teacher candidates (N = 29) to compare immersion teacher education programs at Canadian universities with the goal of better understanding how they develop learners' Teacher Content-Language Awareness (TCLA) and what challenges they face. Findings include the urgent need to establish general guidelines for content-based teacher education programs as well as the need to include criticality as a fundamental element to all TCLA domains.