The European Union’s enlargement process has been moving with more intensity than at any moment since the 2004 round, but the policy is now caught between geopolitical urgency and the structural constraints of accession. The 2025 enlargement package, presented by High Representative Kaja Kallas and Commissioner Marta Kos in November, identified Montenegro, Albania, Ukraine and Moldova as the four candidates that advanced furthest on reforms over the preceding twelve months. Each is described in Commission language as having ambitious goals to conclude negotiations within a defined window, with 2026 framed as a moment of testing rather than completion.
Montenegro is the most advanced. The country has closed four negotiation chapters and was assessed as capable of finalising another six in 2026, putting it on course to conclude accession negotiations within the year if the political crisis triggered in late 2024 by disputes over judicial appointments does not recur. The benchmark for membership has been set as 2028. Albania follows on a similar trajectory, with negotiations advancing across cluster groupings introduced under the revised methodology of 2020.
On the eastern flank, Ukraine and Moldova have been deemed by the Commission to be technically ready to begin opening clusters in line with a target of concluding talks by 2028, but the formal opening of negotiations remains blocked by Hungary. The Commission and the rotating Council presidency have been advancing technical preparatory work, including screening exercises and bilateral conferences, but the political requirement for unanimity at intergovernmental conferences means that bilateral disputes can stall the entire process. Moldova’s parallel integration into the Single Euro Payments Area system, the activation of EU roaming arrangements in 2026, and customs cooperation with the Union show how integration can deepen even before formal accession.
The structural problem is that the EU’s own institutional reform agenda has not kept pace with enlargement ambition. Internal reform of voting rules, decision-making procedures and budget design has stalled, while the candidate countries’ readiness remains the focus of detailed annual reports. Some member states, notably Germany, have insisted that absorption capacity must remain a binding criterion and that gradual integration models should be considered. The German Institute for International and Security Affairs has argued in published research that Ukraine should be treated as a special case while Western Balkan accession proceeds on the established methodology, with a new association framework developed in parallel.
The political economy of enlargement has also changed. Where previous rounds rested on a consensus that membership would be welfare-enhancing for both candidates and incumbents, today’s debate is shaped by concerns over agricultural budgets, cohesion transfers, labour market effects and the geographical balance of qualified majority voting. Montenegro, Albania and Moldova together would change the demographic composition of the Union only marginally, but the fiscal implications of Ukrainian accession would be substantial, particularly for the Common Agricultural Policy and the cohesion envelope. Some studies suggest that with current policies unchanged, Ukraine could become the largest single recipient of EU funds, a fact that will require either policy reform, transitional arrangements, or both.
Beyond the front-runners, the picture is mixed. North Macedonia and Serbia have seen negotiations stalled by separate political dynamics, the former by disputes over constitutional changes related to its bilateral relationship with Bulgaria, the latter by concerns over rule of law, media freedom and foreign policy alignment. Bosnia and Herzegovina has held candidate status since 2022 but progress has been uneven. Kosovo remains a potential candidate. Türkiye and Georgia are in effect frozen. A new northern dimension is now plausible. Iceland’s government has announced a referendum, scheduled for August 2026, on whether to resume the accession negotiations it suspended in 2013.
What emerges from the data is a process moving on multiple speeds. The front-runners need political momentum to close on their stated timelines, the EU needs to reform its own institutions to absorb new members, and the geopolitical stakes of failing to deliver, particularly for Kyiv and Chișinău, are now the highest in the policy’s history. The next eighteen months will indicate whether the 2028 horizon is realistic or aspirational.
