Students increasingly participate in digital and AI-mediated activities outside school, accessing knowledge through multiple languages. However, CLIL (Content and Language Integrated Learning) pedagogy has not fully conceptualized how these practices may contribute to developing bi-/multilingual disciplinary literacies (BMDLs). This study examines the alignment between CLIL teachers’ perceptions and students’ self-reported use of extramural digital and AI-mediated tools. Data were collected through two large-scale surveys across Europe (teachers, n = 578; students aged 9–21, n = 4,229) and statistical analyses (Z-tests and Welch’s t-tests) were used to compare reported frequencies of technology use in the CLIL language across contexts. Results reveal a systematic and statistically significant underestimation by teachers of students’ digital and AI-related engagement. While students report extensive use of digital and AI-mediated practices outside school, teachers’ classroom use remains largely limited to presentation-oriented technologies. These findings suggest that CLIL practice still appears to emphasize functional uses of technology, with limited attention to its epistemic role in supporting disciplinary meaning-making. The study contributes to ongoing debates on digital and AI-mediated activity in CLIL by positioning learners’ extramural digital practices as potential sites for BMDL development and highlighting the need for teacher education that connects students’ digital lives with content and language learning.