Time constitutes social life and time management is central to the everyday conduct of international politics. For some reason, however, the practice turn in International Relations (IR) has produced knowledge about how past practices constitute international politics but not about how the future is also a constitutive feature in and on social life. Introducing a novel perspective on practice and temporality, the article argues that intersubjectively situated representations of the future by practitioners in international politics contribute substantially to our understanding of political processes and the making of international politics. To develop what appears a contradiction in terms – that ‘future-practices’ are driven by tacit know-how and conscious reflection simultaneously – the article develops the concept of doxic futures: representations of the future rooted in practical knowledge and tacit assumptions about the self-evident nature of the social world. The argument is illustrated with a case study of European security and defence diplomacy after the UK voted to leave the EU. Through the envisioning of two concrete doxic futures, a ‘Europe of buying together’ and the UK as a third country in EU defence, diplomats effectively tried to save European security and defence cooperation from the potentially disintegrating effects of Brexit.