The UK Government has proposed national roaming to ensure that consumers may use rival mobile networks in areas where their own operator does not offer (network) coverage (these are known as “partial not-spots”). The proposed policy aimed at increasing the likelihood of mobile subscribers being able to make and receive calls. While this may raise a number of issues, including the risk of higher prices via higher costs and collusion, this article focuses on only one question: whether national roaming, rather than making it more likely that consumers in partial not-spots may be able make and receive calls, may achieve the very opposite outcome. This is because, under national roaming, and depending on the level of the charge, mobile operators may have the incentive to withdraw their network coverage and roam instead.