NATO’s Baltic Sea Blockade

While most of the world is looking at the current crisis in the Strait of Hormuz, northern European nations have been concerned about maritime traffic that flows through the Baltic Sea for several years. After Russia invaded Ukraine in 2022, two countries were so alarmed by the escalation that they decided it was time to join NATO. Finland and Sweden, who share a land border with Russia, believe that joining the alliance will help bolster the military alliance. This has been seen as especially helpful in securing the Baltic Sea and its surrounding neighbours recognise the importance of robust defence in the region. Many politicians believed that the alliance surrounding “NATO Lake” would deter Russia from overt actions, but there have been recent incidents that have questioned that idea.

The Baltic Sea is important to Russia for several reasons. Russia’s territory Kaliningrad is surrounded by NATO nations where their Baltic Fleet and nuclear-capable missiles are housed. This region is not accessible by land without travelling through a NATO country as it is surrounded by Poland and Lithuania. Although, there is a scenario that the alliance considers strategically possible where “Russia could form a land bridge from Belarus to the Kaliningrad exclave along the so-called Suwałki Gap, severing the Baltic states, including Lithuania, from other members of the Atlantic Alliance.” This would be a severe escalation but important if Russia is not able to get to Kaliningrad by sea. Free access via maritime routes are also important to Russia’s economy. St. Petersburg is the second largest city, which sits on the Gulf of Finland and leads to the Baltic Sea. This is a major route for oil exports as well as many other consumer goods. With NATO building up around the Baltic Sea, Russia is suspected of disrupting infrastructure to ensure safe passage to Kaliningrad and their economic exports.

There has been no definitive proof of sabotage from Russia, most European countries are blaming Russia for the recent disruptions on critical infrastructure in the region. Some of the incidents that have escalated tensions in the Baltic Sea are:

“In September 2022, two Nordstream gas pipelines were ruptured by explosions, off Denmark’s Bornholm island. In October 2023, the BalticConnector gas pipeline and nearby communications cables, all running between Estonia and Finland, were damaged. In November 2024, the Arelion internet cable linking Sweden’s Gotland island to Lithuania and the C-Lion 1 telecommunications cable connecting Finland and Germany were cut. In December 2024, the EstLink2 power cable plus several internet cables, again all running between Estonia and Finland, were damaged.”

A recent study from the thinktank RAND puts the daily cost of repairing an undersea telecoms cable at €24m ($28m), an oil pipeline at €36m and a gas pipeline at €75m. As seen in the picture below from the Economist, the Baltic Sea is criss-crossed with communication lines, gas pipelines, and power cables through the use of dragging anchors along the seabed by shadow tankers or drones launched from Russian-linked vessels. 

European countries are attempting to crack down on shadow tankers sailing through the Baltic Sea, but it is a difficult process with the many layers of secrecy shrouding the vessels. This has also led Russia to plans to deploy naval convoys to protect its shadow fleet through the Baltic Sea. Estonia has floated the idea of “a contiguous zone, which can be up to 12 nautical miles wide from the 12-mile territorial sea, [which] allows the country to conduct searches in the Gulf of Finland on military ships and civilian vessels to monitor compliance.” Unfortunately, this will be difficult to enforce on the international level. The United Nations Convention on the Law of the Sea guarantees ships, even sanctioned ones, the right to pass through international straits as long as they do not threaten force or violate safety rules. This includes sanctioned vessels, which is problematic for the Russian ships that are sanctioned. Although, with a Russian escort, it may deter European militaries from escalating the tensions within the region and decide not to conduct searches. It may lead to more traffic from more maritime vessels in an area that is already very busy.