Differentiated disintegration affects the European Union (EU), the departing state and their interlocutors. This chapter contributes to research on processes of differentiated disintegration by focusing on its implications for third countries. As an interlocutor of the UK and the EU, Australia is presented as a case to examine the implications of Brexit, and differentiated disintegration, for a third country. Australia must now adapt to this new form of differentiated disintegration in its relations with the EU and in engaging with the UK. The negotiation of a framework agreement between the UK and Australia will be a vital first step in consolidating the future trajectory of a UK-Australia partnership. The basis for such an agreement has been established over several years of Australia-UK dialogue and agreements, which is particularly evident with the Australia-UK Ministerial Dialogue. We argue that both partners are at a stage where mutual interests and a commitment to both pragmatism and incrementalism will serve as a basis for a renewed and enhanced bilateral relationship. At the same time, Australia will need to recalibrate its perceptions of, and relationship with, the EU27.