Montenegro’s drive to join the European Union by 2028 could be derailed by unresolved disputes with Croatia, raising fears that bilateral tensions may once again overshadow a Western Balkan country’s progress on reforms.
Podgorica aims to provisionally close all remaining negotiating chapters by the end of 2026, an essential step towards its target of becoming the EU’s next member two years later.
Croatia, however, has reminded its neighbour that accession requires the unanimous approval of all 27 EU members. Zagreb wants outstanding wartime, maritime and property disputes resolved before Montenegro completes the process.
The tensions underline a persistent weakness in EU enlargement: bilateral disagreements can become leverage even when a candidate country makes progress on the formal membership criteria.
North Macedonia is the region’s clearest warning. Its accession path was delayed for years by the name dispute with Greece. After resolving that conflict through the Prespa Agreement, Skopje encountered new demands from Bulgaria concerning history, language and constitutional recognition.
Croatia faced a similar obstacle during its own accession negotiations when Slovenia blocked progress for almost a year over their maritime border dispute in the Bay of Piran. Negotiations resumed after Zagreb and Ljubljana reached a political agreement.
Croatia has not imposed a blanket blockade on Montenegro. It has supported the closure of most negotiating chapters but has maintained reservations over Chapter 14, covering transport policy.
Chapter 31, dealing with foreign, security and defence policy, has remained blocked since 2024, when Montenegro’s parliament adopted a resolution on the Jasenovac concentration camp. Zagreb described the move as politically motivated and provocative.
Croatia says time is running out
Croatia’s Foreign and European Affairs Ministry warned on July 22 that only a few months remained before the end of 2026 and urged Montenegro to intensify talks on unresolved issues.
The statement followed EU Enlargement Commissioner Marta Kos’s visit to Zagreb for meetings with Croatian Prime Minister Andrej Plenković and Foreign Minister Gordan Grlić Radman.
European Commission spokesman Guillaume Mercier said the accession process must remain based on candidates’ concrete reform results but added that good relations between current and future members were an integral part of enlargement.
Croatia is seeking compensation for former prisoners held at the Morinj camp, progress in locating 14 people missing from the 1990s war, prosecution of war crimes and settlement of Croatian citizens’ property claims.
Zagreb also wants guarantees for the preservation of a memorial plaque at Morinj, further negotiations on the maritime border and the return of the Jadran, a naval training ship claimed by both countries.
Podgorica calls for dialogue
Montenegro’s Foreign Ministry said on July 23 that all outstanding disputes should be addressed through direct dialogue and in the spirit of good-neighbourly relations.
“Montenegro remains committed to finding sustainable and mutually acceptable solutions to all open issues,” the ministry said.
Podgorica presented Zagreb’s statement as confirmation that both countries share an interest in successfully completing Montenegro’s European integration.
The dispute nevertheless exposes a strategic risk for Montenegro. Its membership bid may depend not only on reforms, judicial independence and alignment with EU policies, but also on whether it can reach political compromises with Croatia.
For Brussels, the case poses a familiar dilemma: how to protect the legitimate interests of member states without allowing bilateral disputes to repeatedly obstruct enlargement.
Montenegro remains the most advanced EU candidate in the Western Balkans. But as North Macedonia’s experience demonstrated, being technically closest to membership does not guarantee crossing the finish line.