The purpose of this contribution is to explore the apparent conflict between the promotion of student mobility on the one hand and the interests of the Member States in ensuring the (financial) sustainability of their higher education system on the other. To this end, the paper is divided into three parts. The first part presents an overview and analysis of the legal principles applying to student mobility developed by the Court of Justice in its case law. The second part explores and analyses both sides of the debate as to whether Member States should be able to invoke budgetary concerns as ground for justification for a restriction of the rights of mobile students set out in the first part. The third part finally argues that as a general principle, such unilateral attempts at restriction by the Member State should be rejected but that at the same time there is cause to take the concerns of these Member States seriously. In the end, it is suggested that a multilateral approach at EU level is perhaps the only solution capable of addressing the conflict.