Baltic Sea Military Drills: NATO's Most Important Exercise Nobody Is Covering

NATO is conducting unprecedented military exercises in the Baltic Sea as Sweden and Finland complete their integration into the alliance. Here is what the drills actually involve.

The Baltic Sea exercises that NATO member states are conducting in the spring of 2026 — less publicized than the Cold Response 26 Arctic exercise in Norway but arguably more strategically significant — represent the first comprehensive test of the alliance's Baltic Sea operational capability since Sweden and Finland completed their accession process.

The inclusion of Sweden and Finland in NATO has fundamentally transformed the Baltic Sea from a body of water where NATO and non-NATO navies coexisted in an awkward choreography of implicit rules, into what alliance planners now describe as a 'NATO lake': an enclosed sea surrounded almost entirely by alliance members, in which Russian naval operations can be monitored, constrained, and if necessary confronted from all directions simultaneously.

The current exercise, operating under conditions of partial information management that means full details are not publicly available, involves naval forces from Germany, Denmark, Poland, Sweden, Finland, Estonia, Latvia, Lithuania, and US naval assets that periodically participate in European maritime exercises. The operational scenarios being tested include submarine detection and engagement, electronic warfare in the Baltic's particularly challenging acoustic environment, and coordinated air defence against simulated cruise missile attacks.

For Sweden and Finland, the exercises are not just military training. They are a visible demonstration of the security guarantee that NATO membership provides — a demonstration that matters domestically in countries where the decision to join NATO required overcoming decades of neutrality tradition and where public support for membership is substantial but not without dissent.

For Russia, which maintains a Baltic Fleet based at Kaliningrad and Baltiysk with surface combatants, submarines, and coastal defence systems, the changed Baltic security environment represents a genuinely deteriorated strategic position compared to the pre-Swedish, pre-Finnish accession period. How Russia responds to this deterioration — whether through military investment, diplomatic protest, or hybrid operations — is one of the most closely watched questions in European security analysis.