Sweden is preparing for a Russian threat in the Baltic Sea

The Russian threat in the Baltic Sea is pushing Sweden to plan for scenarios across the full escalation ladder, as senior military officials warn that Moscow is taking greater political and military risks near Swedish territory and NATO’s northern flank.

Ewa Skoog Haslum, head of the Swedish Armed Forces’ Operations Command (Insatsledningen), said Sweden has prepared for a wide range of possible developments, from hybrid operations to more serious military escalation. Her comments come as Sweden, now a NATO member, assesses whether Russia could try to test the Alliance’s cohesion through a limited action in the Baltic Sea.

Swedish defence plans for escalation before NATO decides

Sweden’s Supreme Commander (Överbefälhavaren, ÖB), Michael Claesson, has repeatedly warned that Russia could seek to test NATO by occupying a small, uninhabited island in the Baltic Sea. Such an operation would not necessarily be designed to defeat NATO militarily, but to create political uncertainty over whether the Alliance should invoke Article 5, NATO’s collective defence clause.

Skoog Haslum stressed that Sweden would not wait passively for a decision by the North Atlantic Council, the political body that must agree on any Article 5 response. NATO members, she said, retain a national responsibility to plan for and prevent attacks on their own territory. Sweden would also support a neighbouring country if it came under pressure.

This reflects a broader shift in Swedish security policy since Russia’s full-scale invasion of Ukraine in 2022 and Sweden’s accession to NATO in 2024. Sweden now combines national defence planning, bilateral cooperation with Finland, Nordic defence coordination, EU security commitments and NATO deterrence.

Why the Russian threat is focused on the Baltic Sea

The Baltic Sea has become one of Europe’s most sensitive security areas. Since Finland and Sweden joined NATO, almost all coastal states around the Baltic Sea are now members of the Alliance, with Russia retaining access through the Kaliningrad exclave and the St Petersburg area.

Swedish officials see the region as vulnerable not only to conventional military pressure, but also to operations kept below the threshold of open armed attack. The Swedish Defence Committee has pointed to recurring sabotage, cyberattacks, GPS interference, airspace violations and other incidents in the Baltic Sea region with different kinds of Russian links.

In the coming years, Swedish defence planners expect Russia to continue relying heavily on hybrid methods. These can create disruption and test state responses while avoiding a direct military clash with NATO. For Sweden, the challenge is therefore not only to prepare for a high-intensity conflict, but also to detect and respond to ambiguous actions at sea, in the air and against critical infrastructure.

Skoog Haslum said she trusts NATO to act quickly in a crisis. “If we did not trust that, we would not trust NATO at all,” she said, according to Sweden Herald.

At the same time, her remarks underline that NATO’s collective defence does not replace national readiness. Sweden has defence arrangements with Finland that also apply outside peacetime, and the two countries have built one of Europe’s closest military partnerships. Their NATO membership has strengthened the Alliance’s northern posture, but it has also increased the need for fast coordination in the Baltic Sea and the High North.

The EU dimension also matters. The European Union’s mutual assistance clause provides another layer of political commitment among member states, although NATO remains the main framework for collective defence in Europe.

Hybrid threats and the shadow fleet raise the pressure

Russian naval activity in the Baltic Sea has increased, partly in connection with the protection of vessels linked to Russia’s so-called shadow fleet. These ships are used to transport Russian oil and other goods while avoiding or complicating Western sanctions enforcement.

The shadow fleet has become a major concern for Nordic and Baltic countries because of its possible links to environmental risks, sanctions evasion, espionage and damage to undersea infrastructure. Several incidents involving cables, pipelines and navigation interference have heightened the perception that the Baltic Sea is already a theatre of low-level confrontation.

NATO has responded by strengthening its maritime presence through Baltic Sentry, a multi-domain activity launched in 2025 to improve the protection of critical undersea infrastructure. The initiative uses frigates, maritime patrol aircraft, naval drones and national surveillance assets to increase situational awareness and improve the ability to detect threats.

Sweden says the risk is low, but readiness must be constant

Skoog Haslum assessed that the probability of Russia trying to seize a piece of NATO territory is currently low. However, she added that the global situation is turbulent and unpredictable, and that such an assessment could change quickly.

Her central message was therefore one of preparedness rather than alarm. Sweden’s Armed Forces say they have a strong situational picture around the Baltic Sea and are planning for unexpected developments. The aim is to avoid being surprised by an escalation, whether it comes through a limited military move, a hybrid operation or a maritime incident.

For Sweden, the Russian threat is no longer an abstract question of long-term defence planning. It is a daily operational challenge in a region where NATO deterrence, Nordic cooperation, EU resilience and national readiness increasingly overlap.