As multilingualism continues to gain importance in modern-day society, the pedagogical translanguaging approach has emerged as a means of facilitating fluid multilingual communication. Given the monolingual practices commonly observed in the CLIL classroom, this study aimed to explore primary school teachers’ beliefs regarding the use of translanguaging and the role of the L1. The data were collected via an online questionnaire including both Likert-scale and open-ended questions, which was distributed to 45 in-service CLIL content teachers in Andalusia (Spain). The results revealed that the participants’ beliefs generally aligned with the principle of fluid language use that is inherent to translanguaging, thus demonstrating a certain openness to furthering multilingual practices in the classroom. However, the participants were more hesitant to define specific roles for the L1 in their classrooms, which could perhaps be the result of persistent monolingual beliefs or a lack of training in how the L1 can be used in multilingual classrooms. Considering such results, it would be beneficial to improve teacher training on the translanguaging approach and the value of the L1 in order to further promote multilingualism.