This study explores language choice patterns during group work of bilingual pupils (Turkish-Dutch) in two mainstream primary schools in Flanders (Belgium). In each school, a group of four children performed eight different tasks, related to different subjects of the curriculum. During task performance, they were exceptionally invited to use their mother tongue (Turkish), which ran against the rules of the monolingual school. Language choice data in these temporary 'multilingual islands in a monolingual sea' were gathered. Results indicate that Turkish was used for purposes related to task performance throughout all tasks. The results challenge the view, currently prevalent in Flemish education, that a submersion approach is the only viable option for bilingual pupils speaking a minority language.