During almost 30 years of NATO partnership cooperation, Finland developed its own defence, its own capabilities and its interoperability with NATO in many ways. NATO membership will affect Finland’s international security and defence policy cooperation and priorities, but no major changes are expected.

The bilateral Defence Cooperation Agreement (DCA) signed with the United States in 2024 complements the cooperation included in Finland’s NATO membership. The agreement provides a foundation for cooperation with the United States in all security situations. It also facilitates the entry and movement of U.S. troops into the country, as well as the deployment of troops and the pre-stockpiling of defence materiel.

According to a Government Report, Finland’s NATO membership will raise the threshold for the use of military force in the Baltic Sea region and will increase stability there. Finland’s strong defence and crisis resilience is also considered to strengthen NATO and the alliance’s collective defence. Finland is part of NATO’s collective defence and is therefore subject to NATO’s security guarantees under Article 5.

The cornerstone of EU defence cooperation is the EU’s Common Security and Defence Policy (CSDP), which is part of the EU’s Common Foreign and Security Policy (CFSP) and the EU’s external relations. The nature of EU defence cooperation has changed because of changes in the security environment. The EU Treaty contains a mutual assistance clause that obliges member states to provide substantial assistance to each other.

Important issues for Finland in the EU’s Common Security and Defence Policy include the development of rapid reaction forces and capability cooperation in order to avoid overlapping and inefficient defence materiel procurement. Finland participates in key cooperation projects, such as the Permanent Structured Cooperation (PESCO), the defence planning review process (Coordinated Annual Review on Defence, CARD) and the European Defence Fund project. The EU can also contribute to the security of supply by harmonising defence industrial markets. Finland has participated in almost all EU crisis management operations. The Finnish Defence Forces also participate in European Defence Agency (EDA) projects.

There are several multilateral initiatives and groups of countries in Europe that support defence cooperation among European states:

• the British-led Joint Expeditionary Force (JEF),
• the Framework Nations Concept (FNC) led by Germany,
• the European Intervention Initiative (EI2) led by France,
• the Northern Group,
• Nordic Defence Cooperation (Norfefco),
• the Nordic and Baltic countries’ (NB8) defence cooperation.

The importance of JEF defence cooperation is expected to increase. In addition to the United Kingdom, the JEF includes the Netherlands as well as the Nordic and Baltic countries. The group’s operational focus is on Northern Europe. A key strength of the JEF is its flexibility, as it is a loose cooperation framework without a formal organisation. The JEF is considered to complement NATO’s deterrence and defence in Finland’s neighbouring areas, particularly in situations where NATO’s Article 5 has not been activated. Exercises carried out under the JEF framework play an important role in the training activities of the Finnish Defence Forces.

Due to Finland’s and Sweden’s NATO membership is expected to deepen Nordic security and defence cooperation. The Nordic countries have sought military compatibility and closer cooperation in training, materiel procurement and crisis management operations. One of the objectives has been the Nordic countries’ strategic and operational interoperability for crisis situations.

Finland has participated in UN-led peacekeeping operations since 1956. In the 1990s, operations were expanded to cover other international crisis management tasks and non-UN-led operations.