Foreign Policy Research Institute A Nation Must Think Before it Acts Maritime Security Issues in the Baltic Sea Region
Maritime Security Issues in the Baltic Sea Region

Maritime Security Issues in the Baltic Sea Region

In June, NATO conducted a scaled down version of its annual BALTOPS naval drills in the Baltic Sea. But with a heavy emphasis on land-based deterrence since re-independence, the Baltic states and NATO alike have been largely plagued by what experts refer to as “sea apathy” or “sea blindness.” This has led to gaps in capabilities, strategy, and procurements, as well as vulnerabilities related to critical infrastructure under sea and onshore.

In the Baltic Sea Region, the maritime status quo favors Russia. Though its Baltic Fleet is not particularly impressive, Russia could use it to harass military and civilian activity at sea and take surprise offensive military action. In the case of the latter, there is very little that Estonia, Latvia, and Lithuania could do to prevent Russia from projecting power into their port facilities, territorial waters, exclusive economic zones, or other littoral areas. Likewise, in the event of grey zone activities (i.e., hostile activities which generally fall below the threshold of war) and/or surprise offensive military action, there is very little that the Baltic states or NATO could do to stop Russia. Combine that with Russia’s anti-access/area denial (A2/AD) capabilities based in Kaliningrad and the logistical chokepoint of the Suwałki Gap, and the strategic calculus for NATO in the Baltic theater becomes extraordinarily difficult.

The Baltic states face myriad hybrid and conventional threats from Russia in the maritime domain. NATO as a whole is unprepared for Russian aggression at sea. Given the economic and strategic importance of the Baltic Sea itself to the Baltic states and NATO, this situation must be remedied. By strategizing procurements, crisis response, and coastal defense, the long-standing condition of “sea blindness” can be reversed.

Geographic Considerations

Map of the Baltic Sea highlighting narrow access, outlying islands and archipelagos, and jagged coastlines in some localities.

The Baltic Sea is a narrow, confined sea with many jagged shorelines, scattered islands, and other operational hazards. In Estonia, Latvia, and Lithuania, coasts are poorly marked and the waters along these coasts are unusually shallow. In relation to other seas, the Baltic is generally shallow, and low salinity results in further complicated conditions for sailors. Alongside the low salinity, “salt pockets” are common in the Baltic Sea. These pockets have a higher salinity than the surrounding water, creating spots where sound waves deflect. This causes problems for sensors and other navigational and surveillance equipment. Combined with cold winters, the low salt content in the Baltic Sea results in high levels of surface ice. Shipping is confined to channels through the Baltic’s bottlenecks and turns as a result of outlying islands and the unusual characteristics of the water itself.

Bottlenecks, such as the Danish Straits and the entrances to the Gulfs of Riga, Finland, and Bothnia, allow for easy and complete surveillance of the local maritime situation. Each of these routes is heavily traveled, and closely monitored and thoroughly surveyed. However, the geography of the many archipelagos and larger islands creates difficulties for permanent surveillance and provides opportunities to evade observation. As retired Swedish Navy Captain Bo Wallander noted, “It’s easy to hide if you are an aggressor here; there are short transit times and short reaction times,” leaving defenders with little time to react. The islands, especially those belonging to Sweden, Finland, Denmark, and Estonia thus hold critical strategic significance. They are ideal bases, supply hubs, staging areas, and jumping off points for special operations or surprise ambushes. Likewise, bottlenecks may also be blockaded and mined to establish local sea control or denial.

Russian Capabilities

Baltic Sea Fleet

As of 2017, the Russian Baltic Sea Fleet stationed in Kronstadt and Baltiysk features two tactical submarines, two destroyers, six frigates, 23 patrol and coastal combatant vessels, 12 mine warfare and mine-countermeasure vessels, four amphibious tank landing ships, and nine other smaller amphibious landing craft. This fleet has largely been neglected, but has seen modernization programs since 2007. Its Steregushchiy class corvettes are equipped with advanced stealth, radar and electronic warfare systems, and have missile systems that can strike targets on land with precision — a capability new to the fleet. Likewise, the naval infantry brigade attached to the Baltic Sea Fleet has seen improvement and equipment modernization in recent years, and there are plans to increase Russia’s submarine presence in the region.

Though the Baltic Sea Fleet is the weakest of the Russian fleets, the geography of the Baltic Sea combined with Russian naval air force and missile capabilities in the region render the battlespace anything but easy for NATO. Further, the Baltic Sea Fleet is more than capable of surprise offensive action or hybrid warfare measures. As Russia has generally sought to economize the use of force and control the intensity of what it views to be an ongoing conflict with the West by hybrid means, it is critical to address the gaps Russia could exploit in the Baltic states’ and NATO’s security posture in the Baltic Sea Region. 


Air power, especially anti-access/area denial (A2/AD) capabilities, are where Russia shines in the Baltic Sea Region. In the Western Military District, Russia maintains 27 combat air squadrons, six attack helicopter squadrons, and a division of airborne infantry. In terms of overall quantity and quality, NATO maintains superior air forces, but Russia maintains a local advantage, which is reinforced by its A2/AD systems. These include its surface-to-surface Iskander Ballistic Missiles, Kalibr cruise missiles, SA-21 Growler surface-to-air-missiles, and long-range integrated air defense S-400 systems. Likewise, Russia maintains the K-300 Bastion-P coastal defense system in Kaliningrad. According to the Center for International Maritime Security, this system is capable of “searching, detection, tracking and classification of sea-surface targets by active radar; over-the-horizon detection, classification, and determination of the coordinates of radiating radars, using the means of passive radar detection and ranging.”

Map: Effective ranges of Russian A2/AD missile systems. Illustration by Matthew Thomas, map by Cartographer of the United Nations, Creative Commons.

Additionally, Su-27 fighter aircraft and Su-24 attack aircraft may be called into action and scrambled to contest Baltic Sea access at a moment’s notice. Sea mines may also be used as a component of the broader A2/AD system, as Russia could take advantage of the bottlenecks and chokepoints in the Baltic Sea, and could do so relatively cheaply and with plausible deniability given the number of mines still buried from the world wars.

The Russian A2/AD systems can reach far flung destinations from Kaliningrad. All of Lithuania and nearly all of Poland and Latvia are in-range, as are parts of Denmark, Germany, Sweden, and Estonia. However, as Michael Kofman of CNA and the Kennan Institute points out, Russian strategy generally prefers an offensive posture with a damage control defense, rather than developing purely defensive capabilities. This means that A2/AD will largely be used in an offensive capacity. This is generally well understood, but, as Russian strategic thinking generally views purely defensive capabilities as cost prohibitive, there are likely vulnerabilities in the systems which make up A2/AD. Thus, as Kofman argues, A2/AD may be defeatable. However, it is still a critical component of Russia’s posture in the Baltic Sea Region, and a major challenge to military logistics in the event of war in the Baltic theater. If Russia could quickly seal off access by land over the Suwałki Gap and complement this achievement by rendering the Baltic Sea closed to surface and air traffic, it could effectively isolate the Baltic states from the rest of NATO.

Baltic Sea Countries’ Maritime Capabilities and Challenges

As a broader institution, NATO does not maintain a forward presence at sea the way that it does on land. The Baltic states themselves operate very small navies with a primary focus on mine-hunting and clearing. While Estonia, Latvia, and Lithuania have built an extraordinary expertise in this area, they have done so without much attention to other capabilities beyond constabulary measures such as counter-smuggling. None of the Baltic states could deny Russia access, even if all their individual naval assets and sea-borne weaponry were combined. Poland has a moderately sized navy, but the serviceability of its combat ships is questionable. Germany has a substantial naval force in terms of quantity, but it operates well beyond the Baltic Sea. It, too, has been largely neglected and, like Poland, its combat ships may not be ready for action.

The Danish navy is perhaps the most prepared of the NATO member states along the Baltic Sea, but it is modestly sized and, like Germany, operates beyond the Baltic Sea as well. While Finland and Sweden are not NATO members, they are key partners in the region and would undoubtedly play a role in the battlespace should conventional conflict emerge. They have modest naval capabilities tailored to their environment, but Finland’s forces are small and structural problems complicate cooperation between the Swedish navy and coast guard.

On the air side, Estonia, Latvia, and Lithuania are deficient, but the NATO air-policing mission largely fills that gap for peacetime operations. Given the local air force presence within Russia’s Western Military District, however, even this would likely be inadequate in case of attack. The other Baltic littoral states, including Finland and Sweden, offer a decent range of tactical airpower, including a number of F-16s and F-18s, and Denmark’s F-16 contingent has recent high-end operational experience in Iraq and Libya. Further, the US has demonstrated in the recent Spring Storm exercises an ability to quickly respond to a crisis scenario in the Baltics with airpower from the continental United States. Likewise, European NATO allies will also be able to respond quickly with airpower. Thus, the primary gaps for NATO and its partners Sweden and Finland are in intelligence, surveillance, and reconnaissance (ISR) and the surface and subsurface domains in the Baltic Sea Region.

Intelligence, Surveillance, and Reconnaissance (ISR)

Individual states’ ISR capabilities vary, but the Baltic states, NATO, and their partner states Sweden and Finland do not have shared, integrated, and continuous awareness at sea. NATO first achieved a complete picture of the air, surface, and subsurface domains in the Baltic Sea during BALTOPS 2017, a basic condition which should be a continual reality. There are decent cooperative organizations for the objective of improving situational awareness, interoperability, and information sharing among members at the regional and EU level, but these have had varying levels of efficacy. Many are not well attuned to facing hybrid threats, and thus it is possible that Russia could exploit this weakness by using commercial or research vessels for mine laying or grey zone activities. Likewise, geographic factors hamper ISR. For example, Sweden’s radar capabilities are hindered by weather and in some regions, such as Stockholm, a complex archipelagic coast. In the case of Estonia, Latvia, and Lithuania, there is both a lack of situational awareness and a lack of any coordinated means of processing and responding to threats. Reports also point to varying levels of success with information sharing. Given their security environment, these issues are critical. Throughout the region, there is a need for a unified picture of the air, surface, and subsurface domains, but currently this does not exist. The maritime domain contains major critical infrastructure components and this lack of awareness opens the door for Russian hybrid activity in the particularly vulnerable Baltic states.

Hybrid Threats at Sea

The littoral areas of the Baltic Sea Region are home to a host of critical energy infrastructure. In Estonia, Latvia, and Lithuania, key gas interconnectors and facilities such as the Klaipėda LNG terminal are located at sea or onshore and are poorly guarded, if at all. Likewise, the sea itself contains critical communications cables which are unburied and unhidden. If Russia could disrupt energy supply and communications, it could wreak havoc on societal resilience. By wearing down society’s ability and willingness to resist aggression, Russia stands to have much to gain. Likewise, Russia has been known to harass civilian and military activity at sea and conduct military operations within other countries’ exclusive economic zones. Port and supply chains are also vulnerable to Crimea-esque “little green men” operations and, perhaps more likely, cyberattack. These vulnerabilities could be exploited to complement overt aggression or to simply cow political leaders into making policy decisions in line with the Kremlin’s objectives. As hybrid activities tend to fall below the threshold of war, they also challenge NATO’s solidarity and commitment to Article V, which states that an attack on one member constitutes an attack on all.  


For the Baltic states and NATO, the maritime domain is a critical component of the broader battlespace in the event of conflict with Russia. In terms of logistics, it is critical to maintain supply and communication lanes through the Baltic Sea. By attacking from both land and sea, Russia could attempt to put the Baltics in a chokehold, isolated from the rest of NATO. Likewise, it is a probable theater for hybrid activity full of vulnerabilities, which, if exploited, could complement overt offensive action or serve as a tool of political subversion and coercion. But, with a renewed focus on the maritime domain, problems addressed can be remedied or at least mitigated and managed. To improve security in the maritime domain in the Baltic Sea Region:

  • The Baltic states and NATO alike should develop clear, comprehensive maritime strategies for defense and deterrence in the Baltic Sea. For the Baltic states, this strategy should identify important investments that can be made in improving ISR capabilities for robust maritime awareness. This is a critical component to the security of the region, and should be implemented by Estonia, Latvia and Lithuania together so as to maintain interoperability, reduce costs, and establish local capacity to detect and process threats quickly. For NATO, this strategy should identify opportunities for power projection into the Eastern Baltic Sea to set up a continuous deterrent posture while at the same time managing the risk of provocation. This may be easier said than done, but it is essential to policing the region.
  • In the Baltic Security Strategy Report, Capt. Bill Combes (US Navy ret.) suggests implementing a combined and cooperative Naval Operations Center, based in the Baltic states, to facilitate higher-end NATO operations locally. Alongside this, he suggests a joint-Maritime Command Center which would identify and process threats in order to quickly establish command and control in crisis and determine how best to respond. These recommendations pair nicely with the creation of local and NATO strategies, and should be incorporated therein. Complementing improvements in ISR, the establishment of command and control locally will drastically reduce Russia’s ability to catch the Baltic states and NATO off guard with either hybrid or conventional operations. Further, practicing command and control will not only help establish protocols for response, it will allow NATO and the Baltic states greater opportunity to rehearse command and control procedures in preparation for crisis scenarios.
  • As Dr. Tadas Jakštas with the NATO Energy Security Centre of Excellence notes, critical energy and communications infrastructure could be disrupted by activity at sea, major critical infrastructure components and facilities onshore lack basic physical security, and many are vulnerable to cyber attacks. The Baltic states, Sweden, Finland, Poland, Denmark, and Germany should focus on improving the security of both publicly and privately owned infrastructure. In the case of privately owned infrastructure, public-private partnerships may be a promising route for mitigating physical and cyber vulnerabilities. By increasing the security of these cables, interconnectors, and terminals, the Baltic states and others can reduce the likelihood of blackouts and other scenarios that could be employed to break down societal resilience to aggression.
  • NATO members should pursue intelligence on vulnerabilities in Russia’s A2/AD posture to be prepared to mitigate or even neutralize the threat should conflict arise.
  • Greater cooperation and integration should be pursued between NATO, Finland, and Sweden to develop unified and continuous surveillance of the Baltic Sea. In so doing, common coordination mechanisms to facilitate information sharing and coordinated regional response should be established.
  • Lastly, the Baltic states and Poland should focus on becoming what Combes and others call effective “coastal powers.” They do not need large blue water navies, but should be capable of defending against violations of their territorial waters, invasion by sea, and controlling their sea assets. This will complement NATO capabilities, and should NATO continue the status quo of its exercise-based deterrence posture as opposed to continuous power projection, it will help to make up for the lack of outside policing in the region as these states will be better prepared to defend themselves.

The current state of affairs in the maritime domain in the Baltic Sea Region is not ideal for NATO. Russia maintains a local advantage in both hybrid and conventional capabilities. In the event of conventional conflict, Russia could attack from both sides and use its A2/AD capabilities to cut off the Baltic states from the rest of NATO in a rapid, modern Anaconda Plan. Hybrid vulnerabilities can be put to the test at peacetime for subversion and coercion. (However, Russia does not view the current state of affairs to be “peacetime,” but rather a continuously fluctuating conflict, as seen through its perceptions of NATO and its activities in the grey-zone.) These could also be exploited to complement overt, conventional aggression to break down societal and governmental structures. But, by addressing critical gaps in procurements, capabilities, and strategy, this condition can be improved. If NATO seeks either to avoid war or come in as defenders rather than liberators, it is essential that the maritime domain finally receive the attention it deserves.

The views expressed in this article are those of the authors alone and do not necessarily reflect the position of the Foreign Policy Research Institute, a non-partisan organization that seeks to publish well-argued, policy-oriented articles on American foreign policy and national security priorities.