Extraterritorial border controls prevent migrants from arriving at the territory of the state and effectively undermine rights to apply for asylum and protections against non-refoulement. As a result, a wealth of scholarship argues that external border controls are illegitimate exercises of state power. This paper challenges two versions of this argument, first, the claim that carrier-sanctions are illegitimate because they subject migrants to morally impermissible forms of coercion and, second, the claim that carrier-sanctions are illegitimate because they subject migrants to (...) illegitimate claims to authority.Against coercion-based accounts of legitimacy, this paper defends the view that while carrier-sanctions are coercive, the coerciveness of a policy is not relevant to its legitimacy. What is relevant is instead whether the authority claimed by the state is legitimate. Against authority-based accounts, this paper argues that states are unable to claim authority in the relevant sense over migrants that are present in the territories of other states.The paper concludes by suggesting that the charge that carrier-sanctions are illegitimate should shift towards the state that allows carriers to enforce these policies on their territories. No state has the legitimate authority to permit other states to pressure carriers to prevent migrants in need of protection from travelling. The state that introduces carrier-sanction legislation, on the other hand, is not exercising illegitimate authority though they may act contrary to demands of justice. (shrink)