Defense ministers from the ten countries that are part of the defense cooperation JEF, Joint Expeditionary Force, have decided to strengthen the naval presence in the Baltic Sea and the North Atlantic in the near future. The reason is the recent damage discovered on cables and wires in the Baltic Sea. For the navy, this means new challenges at sea where cooperation with other authorities and countries is more important than ever. So what are the challenges that Sweden actually faces when it comes to the protection of critical underwater infrastructure?

It started with the sabotage of the gas pipelines Nord Stream 1 and 2 in the Swedish and Danish economic zones, in an area about ten kilometers south of Blekinge. A year later it happens again. Underwater cables and gas pipelines are damaged between Finland and Estonia and between Sweden and Estonia. The difficult environment and the importance of important infrastructure have led to subsurface sabotage becoming a new type of conflict zone, so-called seabed warfare.

It is no coincidence that underwater infrastructure has been marked by numerous sabotages in the past year, 95 percent of internet traffic goes via underwater cables. In addition, there are gas lines and electric cables that are vital for Western society to function in everyday life, as well as in crisis or war. The seabed has become significantly more exploited, new technical equipment, weapons and improved ships get a more robust and efficient opportunity to operate below the surface. However, the water still forms an effective barrier that can hide those who do not want to be discovered. Commander Paula Wallenburg is head of the First Submarine Flotilla and well acquainted with the environment below the surface:

– The underwater battle has clear advantages in that it is carried out in a covert manner and enables operations and intelligence gathering with a low risk of detection compared to similar operations carried out with surface ships or aircraft. The water is impenetrable, submarines and unmanned underwater vehicles have the ability to operate covertly, which also means that the adversary can.


With the hope of eternal peace and limited development of underwater technology, communication cables and gas pipelines were built without any proper protection in mind. The challenge of much of our infrastructure going underwater makes it difficult to monitor. Beneath the surface, the range of various intelligence systems is significantly shorter, which benefits actors who want to damage the infrastructure and at the same time be able to deny it. In the hidden, it becomes easier to carry out sabotage that can be devastating for a country’s functions. Sabotage can take place from surface ships as well as from submarines or underwater craft. It is particularly difficult to protect oneself in the relatively shallow Baltic Sea with its varying salinity and temperature. These factors together affect the subsurface searching sonars and shorten their ranges.

Given that the underwater infrastructure runs over long distances, it is impossible to have control over every meter all the time. Then the cables run over different countries’ territorial seas, economic zones and international waters, all of which have different legal rules, sometimes outdated, about what we are allowed to do as a state, says Chief of the Navy Ewa Skoog Haslum.

The marine presence at sea has increased significantly in recent years due to the deteriorating global situation. The navy’s submarines and ships together with fixed reconnaissance systems such as the radar chain around our coast give a good, but not complete, picture of what is going on out there.

During the next ten-year period, the navy is strengthened, but numbers and endurance are a problem. Two new submarines of the Blekinge class are ordered together with four new surface combat ships of the Luleå class. The minesweepers, originally from the 1980s, are experts at searching for things below the surface and will be life-extended. The problem is that these reinforcements won’t arrive until the late 2020s.

Sweden has a small navy and considering our large territory at sea, we would need to be significantly larger to have a longer endurance and be in several places at the same time, says Ewa Skoog Haslum.

Together with NATO’s naval forces, within the framework of JEF, and other partner nations, the Swedish Navy monitors the Baltic Sea and other surrounding waters. On 15 February this year, the NATO alliance started a collaboration on the protection of the Baltic seabed. Although Sweden is not yet a NATO member at the time of writing, we are included as a partner in the ongoing cooperation. With each sabotage attempt, NATO has strengthened its presence in the Baltic Sea. After the latest sabotage against the Finnish-Estonian lines in October, NATO increased its activity further by deploying aerial surveillance, more underwater drones and ships for surveillance. This shows that Sweden is not alone in facing the threat.

Cooperation with others is the key to increased security in the Baltic Sea. As an alliance member, we will both be able to share, but also gain access to more intelligence information ourselves and thus work proactively and more efficiently. But it is quite clear that both we, NATO and other countries take the issue very seriously, concludes Ewa Skoog Haslum.