The Western Balkan region needs credible European development prospects to break the cycle of enlargement and accession fatigue and to speed up regional adjustment to the EU. Post-accession EU budget flows can provide the necessary funding for such prospects. This article assesses the expected changes in the size and composition of EU budget flows to the Western Balkan countries after their EU accession. Our results show a sudden and substantial increase in gross and net flows, which gradually intensifies over several years before levelling off. EU budget flows are economically important relative to the size of the Western Balkan economies, and their composition is strongly biased towards development policies. We also find that Western Balkan enlargement comes at a minimal budgetary cost for the remaining EU member states. Our findings can help reduce scepticism behind the Western Balkan countries' accession fatigue and the EU's enlargement fatigue.