How EU enlargement works

The EU integrates new members through the enlargement process once they meet a number of political and economic conditions. Each candidate country has to fulfil the same conditions and complete the same steps.

What is EU enlargement?

Enlargement is the process whereby states join the European Union after they have fulfilled a set of political and economic conditions.

Any European state which respects EU democratic values and is committed to promoting them may apply for EU membership.

Accession criteria

The accession criteria, or Copenhagen criteria (named after the 1993 Copenhagen European Council meeting which defined them), are the essential conditions all candidate countries must satisfy to become an EU member state. These are:

political criteria: stability of institutions guaranteeing democracy, the rule of law, human rights and respect for and protection of minorities
economic criteria: a functioning market economy and the capacity to cope with competition and market forces
administrative and institutional capacity to effectively implement the EU acquis (body of common rights) and ability to take on the obligations of EU membership

The EU's capacity to take on new members, while maintaining the momentum of European integration, is also an important consideration.

European Council - Copenhagen, 21/22 June 1993

Accession steps

After a state has applied for EU membership and its request has been agreed to by all EU member states, the accession process can begin. The opening of the formal accession negotiations requires the agreement of all EU member states. Those negotiations help prepare the candidate for eventual membership and focus on the adoption of established EU law and implementation of the required judicial, administrative and economic reforms.

When negotiations on all policy areas have been completed, and the EU itself is prepared for enlargement in terms of absorption capacity, then the terms and conditions for accession – including possible safeguard clauses and transitional arrangements – are incorporated into an accession treaty. This treaty needs the European Parliament's consent and the Council's unanimous approval before all EU member states and the candidate country can sign it.

After all the contracting parties have ratified the accession treaty in line with their respective constitutional rules, the candidate becomes an EU member state on the date set out in the accession treaty.

Role of the Council

The Council (under the General Affairs Council configuration) supervises the EU enlargement process and the accession negotiations, which are intergovernmental by nature. On matters related to the enlargement policy, the Council generally operates by way of unanimous agreement between all the EU member states.

Every year, the Council takes stock of progress made on the enlargement process and typically approves conclusions. The latest conclusions were issued on 16 December 2025 by the Danish Council presidency. Those conclusions assessed the situation for each of the EU's partners and set out political priorities and guidelines for further reforms.

Presidency conclusions on enlargement, 16 December 2025

Preparing the EU for future enlargement

The Granada Declaration of October 2023 highlighted that the EU must prepare for future enlargement and that countries seeking to join must advance their reforms. In June 2024, the European Council adopted a roadmap for future work on internal reforms and invited the Commission to carry out policy reviews on the EU's values, policies, budget and governance.

In October 2026, the Commission presented proposals based on those reviews, including ways to prepare EU policies and institutions for a wider EU and to deepen the gradual integration of candidate countries before accession, including through closer participation in strategic areas such as energy, transport, the digital sector and defence, where conditions are met.

The Commission's communication was discussed by the General Affairs Council on 13 October and by EU leaders at the European Council meeting on 15 and 16 October 2026. Leaders reiterated that enlargement is a geostrategic investment in peace, security, stability and prosperity, and that both future member states and the EU must be ready at the time of accession. Candidate countries must continue their reform efforts, notably on the rule of law, while the EU needs to advance its internal reforms and address questions relating to its priorities, policies and capacity to act. Bearing in mind that the accession process is merit-based, EU leaders called on the Council to analyse the Commission's proposals and take work forward.