There is extensive CLIL research on stakeholders' practices, integration of content and language, and pedagogies. However, limited studies report on teachers' pre-existing knowledge before CLIL implementation and how it influences their classroom pedagogy. Using a third space frame, this study examined CLIL implementation in Kazakhstan. It included 15 science teachers who teach science through the English medium of instruction (EMI). A hybrid coding strategy was followed to analyze questionnaires, teachers' science lessons, multimodal teaching-based scenarios, and semi-structured interviews. Our findings revealed that teachers' CLIL implementation was guided by their (1) hybrid beliefs about scientific knowledge and learning, (2) humanising pedagogy, (3) shift to constructivist science pedagogy, and (4) hybrid linguistic stance. We conclude that a third-space perspective diverts the gaze from CLIL teachers' challenges to illuminate the entanglement of teachers' epistemic stance, pedagogical content knowledge (PCK), and linguistic stance as emergent discursive practices when policy borrowings connect global and local epistemologies.