Traditionally, languages have been separated from each other in the school curriculum and there has been little consideration for resources that learners possess as emergent multilinguals. This policy is aimed at the protection of minority languages and has sought to avoid cross-linguistic influence and codeswitching. However, these ideas have been challenged by current multilingual ideologies in a society that is becoming more globalised. Within the field of multilingual education studies, there is a strong trend towards replacing the idea of isolated linguistic systems with approaches that take multilingual speakers and their linguistic repertoire as a reference. This article focuses on translanguaging, a concept that was developed in bilingual schools in Wales and refers both to pedagogically oriented strategies and to spontaneous language practices. In this article, translanguaging will be analysed as related to the protection and promotion of minority languages. Examples from multilingual education involving minority languages will be shown in order to see how translanguaging can be at the same time a threat for the survival of minority languages and an opportunity for their development. A set of principles that can contribute to sustainable translanguaging in a context of regional minority language use will be discussed.