Questions concerning border closures during pandemics often focus on international borders or rights-based considerations. Closures of internal borders in federal countries, such as Canada, raise independent concerns regarding who can close internal borders when. Those questions are not exhausted by rights-based considerations and cannot be resolved using brute empirical measures. They instead implicate the nature and ends of federalism. This text uses the case of internal border restrictions in Canada during COVID-19 to explore whether the kinds of closures that took place there can be justified on federalism grounds. It argues that the case for provinces being able to unilaterally enact interprovincial border closures in federal countries, as observed in Canada during COVID-19, do not withstand scrutiny. It attends to possible justifications for federalism to demonstrate that the best arguments for federalism do not support provincial control over borders that justify provinces possessing, let alone exercising, unilateral authority to close interprovincial borders to persons residing in other provinces.