Swedish Navy encounters Russian submarines “almost weekly” (and there may be more on the way)

The Swedish navy believes that Russia will focus more on submarine raids in the Baltic Sea when there is an agreement for a ceasefire or armistice in Ukraine.

The Swedish Navy is encountering Russian submarines in the Baltic Sea “almost weekly” and expects these encounters to increase once the war in Ukraine begins. reach a ceasefire or armistice.

The forecast is advanced by Captain Marko Petkovic, head of operations for the force, in statements to , where he adds that Moscow has “continuously reinforced” its naval presencewith sightings of Russian vessels now a routine part of Swedish maritime patrols.

The increase in submarine activity comes in the context of a broader escalation of security threats across the Baltic region. Countries around the sea have faced suspicions of hybrid attacks, including drone incursions, potential sabotage of underwater infrastructure and the movement of Russia’s “parallel fleet” – aging tankers transporting crude oil under sanctions and unclear ownership. Petkovic warned that these civil-flagged ships could be reused for drone launchesadding a more unpredictable layer to regional risks.

These types of incidents are not limited to the Baltic area. The UK Defense Secretary reported last month that a Russian spy ship entered British waters and attacked military pilots with lasersframing the episode as part of a “new era of threats” posed by hostile states.

In response to growing pressure, Sweden has intensified cooperation with its NATO allies. The country recently hosted Playbook Merlin 25, an important anti-submarine warfare exercise which involved nine nations, including Germany, France and the United States. Hundreds of military personnel have been trained to detect submarines in the Baltic Sea’s notoriously challenging underwater terrain, where steep formations on the seabed allow vessels to hide from sonar detection.

Petkovic noted that Russia is expanding and modernizing its submarine capabilities, producing approximately one new Kilo-class submarine per year at the naval shipyards in St. Petersburg and the Kaliningrad exclave. “As soon as a ceasefire or armistice is implemented in Ukraine, we believe that Russia will strengthen its capabilities in this region,” he said, stressing that the Swedish Navy must continue to adapt.

Submarine infrastructure in the Baltic Sea remains particularly vulnerable due to poor visibility, complex salinity patterns and temperature variations. Petkovic highlighted that countries such as Sweden, Norway, Finland, Estonia and Lithuania are “totally dependent” on safe shipping lines for communication and vital social functions.

However, NATO’s increased surveillance is producing results. Since the launch of Operation Baltic Sentry in January, no new incidents involving submarine cables have been recorded.