Whilst mainstream schools in England may encourage multilingualism by insisting on the study of foreign languages, multilingual children are not always provided with support for the maintenance of their heritage languages and cultures. In response to this shortcoming, communities organise themselves to support their young members by setting up extra-curricular education institutions or associations, also called complementary schools, which contribute to the cultural and linguistic maintenance of minority communities. Through emblematic extracts from a fourteen-month ethnographic research in an Italian complementary school in London, this article examines how HL learners engage in and reflect on their multilingual practices and how they develop agency in their learning environment. The findings illustrate how critical modes of teaching and learning that make space for multilingualism can provide children with unique opportunities to discover, explore and experiment with their multilingual and multicultural selves, which, in turn, permit them to access linguistic resources and legitimise multilingual learner identities. Expanding on Fishman's notion of 'breathing space', the article suggests that complementary schools represent a space where minority languages but also pedagogical practices can breathe and develop.