SwedenWeekly sightings of Russian submarines in the Baltic Sea

Fabian Boerger

 · 09.12.2025

Sweden: Weekly sightings of Russian submarines in the Baltic SeaPhoto: Fabian Boerger
Submarines are appearing more and more frequently in the Baltic Sea. Here, a German submarine patrols the Kiel Fjord. But the Swedish navy reports: Russia is sending more and more submarines to the region.
The Swedish navy encounters Russian submarines in the Baltic Sea on a weekly basis. This is what Navy Captain Marko Petkovic says to the British newspaper The Guardian. He anticipates a further increase in the Russian presence in the region. NATO is reacting.

According to Petkovic, Russia could even increase its military activities in the Baltic Sea following a possible ceasefire in Ukraine. According to Petkovic, a continuous increase in Russian underwater activities has already been observed in recent years.

Although sightings are common, the number has increased in recent years. According to the Swedish officer, Moscow is systematically expanding its presence. His country's defence capacities would have to be expanded accordingly in order to be able to react to this development.

NATO exercises anti-submarine defence in the Baltic Sea

As a reaction to the increased Russian presence, Sweden was in mid-November Host of the major NATO submarine defence exercise "Playbook Merlin 25". Nine countries took part in the manoeuvre, including Sweden, Germany, France and the USA.

Hundreds of soldiers trained their submarine-hunting skills in the real conditions of the Baltic Sea in preparation for a possible confrontation. The hilly underwater landscape of the Baltic Sea off Sweden makes it considerably more difficult to locate enemy submarines, as they can hide in the rugged topography.

Overall increase in military activities

The repeated submarine sightings are linked to military activities, which have recently increased. A few weeks ago, the Russian landing ship Alexandr Shabalin caused a stir when it repeatedly appeared off the island of Fehmarn. According to NDR research it was escorting a cargo ship of a Russian state shipping company that was presumably transporting war equipment.

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There are also civilian oil tankers in the Russian shadow fleet. Although they do not pose a direct military threat, according to Petkovic, they could be used for military purposes - for example to launch drones.

Importance for sailors

For sailors, the development is also likely to be relevant in the coming sailing season, when further NATO exercises or restricted areas could influence route planning. The following can be expectedn NATO exercises BALTOPS and Northern Coast, which take place every year.

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