As US public education enrolment grows increasingly diverse, school choice policies create opportunities to break the link between residential and school segregation. They also create new pathways for families to self-segregate into ever more racially isolated schools. This study explores student enrolment patterns in Metro Detroit over a ten-year period to understand the implications of open enrolment policy on school racial and economic demographics. By focusing on the ten suburban districts that enrol the most Detroit resident students, we provide initial evidence that, while those districts increasingly enrol more Black and poor students than their residential population, many students from those districts are also taking advantage of school choice policy to enrol in districts further from the Detroit city centre. The in-flow and out-flow of students from these districts has implications for district budgets; design and implementation of school choice policy; and support for students in transitioning school environments.