Tony Lawrence
Head of Defence Policy & Strategy Programme / Research Fellow
September 11, 2025
Hybrid and High-End Warfare in the Baltic Sea Region: Safeguarding our Maritime Domain
Niklas Granholm
Deputy Director of Studies at FOI’s Department for Security Policy and Strategic Studies
Björn Ottosson
Programme Manager for NOTS and a Senior Researcher in FOI’s Department for International Security Policy
Igor Schvede
Former commander of the Estonian Navy (2007-12) and an advisor at the Estonian MoD
NATO has responded to Russia’s war in Ukraine by enhancing its defence and deterrence posture in the Nordic-Baltic region and elsewhere.
This has strengthened the Alliance’s naval presence and power and substantially altered the status of the Baltic Sea in NATO’s regional defence planning and, thus, the responsibilities of and demands on naval forces in the region in peacetime, crisis, and war.
As NATO faces undeclared hybrid warfare in the Baltic Sea region (and elsewhere), the Baltic Sea itself could become a key and complex operational theatre in the event of a NATO-Russia conflict. As a priority, NATO needs strengthened and credible naval capability here, both to deter Russia from believing it can conduct hybrid aggression free from consequences and be emboldened to escalate towards conventional conflict and, in the event of conflict, to ensure sea control in an Alliance context to keep sea lanes open. The stakes are high, and the timeline is short. Deterrence must not wait for perfect conditions. It must begin now, despite the fact that most European Allies are experiencing a period of transition and vulnerability.
Success depends on political resolve, operational readiness, and early, visible action. Allied nations, both in and outside the Baltic Sea region, should:
- Continue to deepen regional cooperation, evolve maritime strategies, and ensure the readiness of forces to operate effectively in a contested and dynamic environment.
- Improve joint situational awareness.
- Increase maritime assets in and available for the Baltic Sea region, including by:
- instituting a collaborative crash-programme for drones.
- creating a Standing NATO Maritime Group for the Baltic Sea region.
- investing in a robust and modern naval presence as an appropriate complement to augmenting land defence.
- Balance planning for hybrid war and high-end operations.
- Discuss options for deterrence by punishment approaches to maritime hybrid attacks.
