EU enlargement in the Western Balkans: All together now?

When the leaders of the EU and the countries of the Western Balkans meet in Brussels on Wednesday for the EU-Western Balkans summit, progress on EU enlargement will be high on the agenda.

After the wars that ripped the Balkans apart in the 1990s, the European Union pledged in 2003 to integrate into the bloc the seven countries of the Western Balkans: Albania, Bosnia and Herzegovina, Croatia, Kosovo, Montenegro, North Macedonia and Serbia.

Croatia joined the EU 10 years later.

Apart from Kosovo, which applied for membership in 2022, the five remaining countries are recognized by the EU as official candidate countries.

How do things stand?

More than a decade after Croatia joined the EU, enlargement in Brussels appears closer to reality than it has in years.

As Brussels signals renewed commitment to enlargement, the question is no longer if, but which countries in the Western Balkans are ready to move forward and which will be left behind.

Montenegro — the smallest of the five candidate countries in the region — is widely seen as the frontrunner in the Western Balkans accession process, with Albania following close behind.

According to EU Enlargement Commissioner Marta Kos, Montenegro could technically complete accession negotiations by the end of 2026 and Albania a year later.

"Then we need one to one-and-a-half years to go through the ratification process. So, I am realistically optimistic that even during my mandate, which ends at the end of 2029, the European Union could have at least two new members," Kos told DW.

In Serbia, the largest and economically strongest candidate in the region, the momentum for reform has clearly waned. In response, Serbian President Aleksandar Vucic suggested last week before travelling to Brussels for a meeting on Serbia's EU progress that all Western Balkan countries should join the EU together.

But is this a viable option, and would it even be acceptable to Serbia's neighbors and the EU?

Montenegro leads the way

The process of enlarging the EU to include the countries of the Western Balkans has been slow for several reasons.

On the one hand, there are unresolved bilateral issues, rule of law deficits and high levels of corruption in the Western Balkans. On the other hand, there has been a degree of reluctance and "enlargement fatigue" on the part of EU member states.

After years of setbacks, Montenegro pushed through key reforms two years ago and forged a broad political consensus on EU membership. Both Podgorica and Brussels now aim to complete the accession process as soon as possible.

Montenegro recently reached a new milestone by closing five accession chapters, which are a prerequisite for joining the EU, but remaining requirements include ensuring final convictions in high-level corruption and organized crime cases, appointing key judicial officials and filling vacant leadership positions in major institutions.

Local critics argue that the reforms are rushed and may lack substance.

"No one seriously claims that the system can be changed from the ground up in a few years," said Montenegro's Minister of European Affairs Maida Gorcevic. "Criticism is legitimate if it accelerates reforms, but it's important to note that progress today is measured by clear European indicators, not political impressions, and Montenegro's progress is objectively confirmed by EU institutions," she told DW.

Albania's progress

Albania, meanwhile, has also picked up its reform tempo.

While the European Commission points to advances in judicial reform, it has also warned that further efforts are needed to fight corruption and strengthen the rule of law.

But, as political analyst Florian Bieber points out, the outcome is far from certain, and sustained reforms are still required.

"Albania is doing a lot of at least formal reforms, but in a context where you have a very strong leader, Edi Rama, [it] certainly has very serious democratic shortcomings. So, there are some reservations, and so, it's unclear whether Albania will be able to close that gap and really be ready by the same time as Montenegro," he told DW.

Why does the EU want to enlarge?

For the European Union, enlargement is both a strategic and a credibility issue.

Integrating Montenegro would be a low-risk, high-impact way to show that the EU can deliver on its promises, reinforcing trust in its leadership in uncertain geopolitical times, according to a European Policy Center policy brief.

Enlargement is also about Europe's security and geostrategic interests.

"We are paying a price for not integrating these countries when they first wanted to join, leaving a region of instability," Commissioner Kos said.

But EU enlargement is also seen as a geostrategic investment in Europe's security and prosperity, says Tinatin Akhvlediani, research fellow at the EU Foreign Policy Unit at the Center for European Policy Studies.

"If the Union does not expand into these countries, other powers could step in and exploit the region, using it as leverage against the European Union, including Russia and China," Akhvlediani told DW.

What about Serbia's suggestion?

So, if the pace of progress towards EU accession is so different across the region, where does this leave Aleksandar Vucic and his suggestion that all Western Balkan countries should join the bloc together?

Many analysts interpret Vucic's proposal as an attempt to slow down the entire integration process.

Within the European Commission, there appears to be little appetite for the idea.

"Accession is a merit-based process. Each candidate should join when they are ready and meet the conditions and criteria set out in the EU Treaties, including the Copenhagen criteria. There are no pre-determined timelines. The process is driven by delivering reforms and demonstrating sustainable results," a European Commission spokesperson told DW.

Each country charts its own course

Both Tinatin Akhvlediani and Florian Bieber emphasized that the enlargement process has always followed the "Regatta principle," meaning that aspiring member states chart their own course, with integration depending on their own merits, reforms and the fulfillment of technical criteria.

Bieber notes, however, that the idea of simultaneous accession has some merits.

"It would avoid creating EU external borders between the Western Balkan countries and prevent bilateral issues from being imported into the European Union," he said.

"That said," he continued, "there are serious shortcomings, because the tempo of the slowest member — or candidate, rather — would dictate the speed for everybody. So, if Montenegro is ready to join the European Union in the coming years, it might be held up by countries like Bosnia-Herzegovina or Kosovo, which might take another 10 years."

Montenegro not willing to wait

The office of the Albanian prime minister had no comment on Vucic's proposal at the time of publication.

Montenegro, however, reacted promptly, making it clear that it wants to push ahead.

"Montenegro does not want to wait for anyone, nor does it expect anyone to wait for us," said Minister Gorcevic. "We are leaders in the process and want to join the European Union when our results show that we are ready and deserve membership."

It was announced late on Tuesday that Serbia will not participate in Wednesday's summit in Brussels.

Vucic announced the decision himself, saying that he is acting to protect Serbia's interests and adding that he made the decision "so that no one else would be blamed and the government would not be exposed to any pressure."

Edited by: Aingeal Flanagan

Correction, December 17, 2025: A previous version of this article attributed the quotes from the Montenegro government to the wrong person. DW spoke to Maida Gorcevic, Minister of European Affairs. The current version has been corrected accordingly. We apologize for this error.