Black Sea Significance to European Security

After three years of fighting, many of the Russian navy’s limitations in the Black Sea have been exposed. The Black Sea Fleet has lost around a third of its combat strength and has been forced from its home port at Sevastopol by the threat of Ukrainian long-range strike capabilities along with Uncrewed Surface Vessels (USVs).

Moreover, the invocation of Article 19 of the Montreux convention by Turkey, limiting the ability of both belligerent parties’ vessels to transit the Bosporus and Dardanelles, creates considerable limitations for both Russia and most NATO members in region. For Russia, should a ceasefire result in a relaxation of the convention, any vessel deployed to the Black Sea would be fixed in the region in the event of re-invocation and a return to hostilities.

Montreux, by design, limits the freedom of action of NATO members not based in the Black Sea. It might, then, be asked whether the region will become, to some extent, a peripheral one for both Russia and NATO, and one which should be accorded secondary importance relative to maritime theatres such as the High North.

While this view is understandable, the Black Sea retains considerable importance within Russian maritime – and the wider – economic strategy. Despite Turkey's access-control, other non-riparian alliance members would be poorly served by a failure to engage with the region.

The Black Sea in Russian Maritime Strategy

The Black Sea has several important functions in Russian maritime strategy. Russia is the world’s second largest oil exporter, with 22% of shipments coming through Black Sea loading points like the Novorossiysk Commercial Sea Port. The impact of oil-related sanctions is well documented, as is Russia’s attempts to circumvent them, including with its shadow fleet.

However, it is notable that Russia’s sanction-related demands during the ceasefire negotiations have pertained to agriculture-related banking access. Black Sea ports such as Novorossiysk and Taman represent the primary export hubs for wheat and grain and are of considerable importance to Russian maritime strategy.

While not as financially significant as oil, the export of agricultural products is an increasingly important part of Russia’s export portfolio. It continues to harvest from land occupied since 2022. In 2024, for example, the value of agricultural exports reached $43 billion. This is a far cry from the value of hydrocarbon exports but nonetheless means that foodstuffs are, in financial terms, Russia’s second most important export product, with the value of exports in this sector exceeding that of pre-war arms exports (traditionally an important source of revenue) twofold.

In years to come, continuing population growth and the impact of climate change on Global South agricultural production will likely grow the value of the agricultural sector considerably. While Russia is unlikely to eliminate its structural reliance on the sale of hydrocarbons, it is hoped that a more diversified export portfolio can allow it to mitigate some of the risks which its current overreliance on energy creates. To some extent this is already the case as rising revenues from agriculture are one factor (albeit among others) which partially offsets hydrocarbon revenue declining in 2023.

The importance of agriculture to the Russian leadership is illustrated by the longstanding practice of setting ambitious export targets for the sector backed by state subsidies. Russia has long viewed exporting strategic goods – and creating reliance on these critical and not easily substitutable products – as a key pillar of its geoeconomic strategy in a world where it will not be one of the major players in terms of GDP.

Food will generate political value well in excess of its commercial value for regions such as the Middle East and North Africa, where food insecurity remains a chronic concern and can impact regime stability. We might remember, for example, that food shortages were a proximate cause for the Arab Spring protests.

Land conflict is also a source of instability in the Sahel region, where Russia is continuing to focus diplomatic efforts. Not only does this provide influence over the region but given the second order effects of instability within the Middle East for Europe, it implies leverage over NATO as well. Russia can see the political opportunities that this provides, as illustrated by its attempts, prior to the fall of Assad, to invest $500 million in a commercial facility near its naval base in Tartus to use as a grain export hub.

Sometime between middle of the next decade and the early 2040s, Russia will also have to grapple with peak oil (the period at which global demand for hydrocarbons is at its zenith) after which we will see a shrinking market for hydrocarbons. Coordination with other oil producers through frameworks like OPEC+ will become increasingly difficult. Not only can agricultural exports offset possible financial losses but if Russia can achieve something approximating a monopolistic position as an exporter of staple foodstuffs to many OPEC nations it will enjoy some leverage in negotiations.

Russia thus has strong incentives to both facilitate agricultural exports through the Black Sea and undercut Ukraine’s ability to export food, in order to extend its own control over these key markets. Thus, even after any ceasefire we should still expect the disruption of Ukrainian maritime trade to remain a long-term Russian aim. If a ceasefire is agreed, we should expect to see a reprisal of the tactics Russia adopted in the Sea of Azov in 2014-2022, in which the obstruction of maritime traffic by the Kerch bridge and periodic harassment of vessels led to a steep reduction in container traffic to and from Ukrainian ports.

One avenue for Russia to achieve maritime trade disruption would be to clandestinely mine the approaches to Odessa and explain any mine strike as being the result of drifting residual Ukrainian mines from the war. Alternatively they could periodically harass and interdict vessels using Russian ships, something which has already occurred near Bulgarian waters. Ukraine could not as easily target naval vessels harassing shipping in the context of a ceasefire.

Finally, during any breakdowns of a ceasefire, Russia is likely to use such periods of conflict to target Odessa.

Given the importance of export markets for Ukraine and NATO, the maritime component of the 100-year partnership between the UK and Ukraine may have a particular significance. Whether Turkey reopens the straits to belligerents’ navies during a ceasefire is important to both sides. If it does, this should allow the Ukrainian mine hunter vessels, stuck in Portsmouth since early 2024, to enter the Black Sea. Additionally, the UK maintains an expeditionary Mine Counter Measures (MCM) capability including Autonomous Underwater Vehicles (AUVs) and other uncrewed systems, which could deploy to the region.

In addition to disposing of mines, systems such as the Towed Synthetic Aperture Module (TSAM) can be used to generate high resolution images of the seabed in critical shipping route and port approaches. Demonstrating the absence of mines should help deter future Russian mining as a breach of ceasefire could be demonstrated easily. This, combined with the activity of the MCM Black Sea group under Turkish leadership, will ideally reduce the current and future mine threat.

Equally, the importance of dealing with harassment by surface ships in a lower-intensity conflict provides an incentive for regenerating a Ukrainian surface-fleet through frameworks like the UK-Ukraine 100-year agreement. Even if vulnerable in high-intensity conflict, these vessels’ ability to conduct peacetime security and policing activity is a requirement for any sovereign maritime state, and vital to limiting Russia’s interdiction and harassment in a ceasefire context where sinking ships with coastal missile batteries may not be an option.

Another consideration is the role of the other navies of the Black Sea. While navies such as the Romanian Navy are recapitalising their forces, the most important player by some distance is Turkey. Turkey’s dominance has been improved considerably by the attrition of the Black Sea Fleet, but control of the straits gives Turkey leverage – although it has tried hard to present itself as an honest broker. The potential role of Turkey and regional navies – should any reassurance force for the security of Ukraine materialise – is one that merits close consideration.

The Black Sea as a Lynchpin of Russia’s Southern Strategy

The second critical role that the Black Sea has is as a lynchpin of Russia’s power projection beyond its immediate environs. Historically, expeditionary squadrons such as the 5th Eskadra (the Soviet Mediterranean squadron) have been subordinated to the Black Sea Fleet since it is from this region that they can be most easily rotated and resupplied. Deploying vessels from further afield, by contrast, imposes considerable demands on a Russian navy, a green-water fleet comprised of frigates and corvettes.

While Russia cannot confront NATO in a conflict at reach, it can engage in more limited activity where the Black Sea Fleet might be central. For example, the fleet served as the logistical backbone of the Russian intervention in Syria in 2015 with Ropucha-class LSTs running a logistical operation dubbed the ‘Syrian Express.’

Success in Syria provided the Russians a greater presence in the Eastern Mediterranean, which allowed it to set up a limited (but not wholly irrelevant) anti-access bubble and engage in actions such as convoying Iranian oil to Syria. Russia’s construction of future amphibious vessels such as the project 23900 is also concentrated in the Zaliv shipyard in Crimea, illustrating the centrality of the Black Sea Fleet in Russian thinking.

As Russia secures access to ports in Sudan and potentially Libya, its coercive and disruptive options increase. In Sudan, Russian vessels and associated systems would straddle the Red Sea, with ramifications in peacetime and conflict. In peacetime, the mere presence of hostile capabilities in an area makes moving military vessels more difficult and costly, with multiple ISR assets dedicated to any single journey. In effect this means that routine naval activity will become more costly and difficult. In conflict, as demonstrated by Houthis in the Red Sea, even a limited sea-denial capability can significantly constrain shipping. Contending with this challenge would draw platforms from the European theatre.

Russia’s extra European maritime hubs, while not formidable, are not inconsequential. These can be symbiotically linked to the Black Sea Fleet. Whilst they can operate even if the Black Sea Fleet is constrained – Tartus was kept running with vessels rotated from the Baltic Fleet after 2022 – this would become more logistically challenging.

The Black Sea Fleet in a Hot War

Despite its limitations, the Black Sea Fleet would be significant in a hot war between Russia and NATO. Though comprised mostly of corvette-sized vessels such as the Karakurt-class, the fleet holds a considerable portion of Russia’s throw-weight for sea-launched cruise missiles.

One 2019 estimate of the Southern military district (comprising the Black Sea Fleet and the Caspian flotilla) found it possessed the launch capacity for 80 long ranged land attack missiles in a single salvo, compared with 85 in the western military district and 56 in the Northern Fleet. This balance has likely shifted with changes to the Northern Fleet, but the Zaliv shipyard is due to deliver 7 further Karakurt-class corvettes to the Russian navy by 2027 (although one, the Askold, was destroyed in a Ukrainian attack). Each Karakurt-class vessel carries 8 VLS (vertical launching system) cells and the forthcoming order of new ships, if bolstering the Black Sea Fleet, will mean it retains a considerable portion of Russia’s overall cruise missile throw-weight.

All this means the fleet can launch cruise missiles from the relative safety of Russian controlled waters. Vessels can be sunk in defended bastions, as demonstrated by Ukraine, but at a significant cost in terms of numbers of munitions expended. There is also threat to aircraft and vessels which must be operated within range of Crimea’s A2AD capabilities. These include long-range SAM (surface-to-air-missile) systems and anti-ship complexes such as the Bastion-P. This is not an insurmountable challenge but a costly one.

The missile threat to civilian targets from the Black Sea would make it politically difficult and costly to exercise sea control at distance even though this might be the most militarily rational approach. Allied navies and air forces would be pulled towards the heart of Russia’s anti-access capabilities even though the Alliance’s advantages compound further from the Russian shores.

The growth of Ukrainian long-range strike capabilities is thus of significance not only to Ukraine but also to NATO, and this should be a key priority of ongoing and future efforts to support Ukraine in the maritime domain. Ukraine has conducted consistent strikes on Crimea using both air-launched storm shadow missiles and ground-launched UAVs. An expansion of its A2AD capabilities to include a larger number of short-ranged ballistic missiles would complicate the Black Sea Fleet’s position. By dint of proximity Ukraine can also employ more expendable systems such as USVs. The growth of Ukrainian anti-access capabilities, assuming coordination with Allied systems in a conflict, would mitigate, though not remove, the challenge posed by the Russian Black Sea Fleet.

The second threat that the Black Sea Fleet would likely pose in a conflict is the mining of chokepoints such as the Bosporus and the multiple avenues for its sea lines of communication. The economic consequences of mining may be limited for members of the alliance. For example, maritime freight comprises 16% of Romania’s freight and an even smaller portion of Bulgaria’s, while Turkey has many non-Black Sea ports. However, mining at chokepoints would complicate the reinforcement of the region by non-riparian Allies. The challenge is fairly well understood, however, with efforts both on a trilateral basis between Turkey, Romania and Bulgaria and across the Alliance to mitigate mine threats.

A more pressing challenge will be anti-submarine warfare (ASW) against the fleet’s six-kilo-class submarines. There is likely to be some capability growth within the region as Romania takes delivery of three French Scorpène-class submarines and Turkey progresses with an ambitious frigate building programme. However, ASW is a task which requires the close coordination of air, surface and subsurface platforms that often necessitates the sharing of sensitive data.

Coordinated ASW in the region will require both political and organisational trust and capabilities to be exercised on a large-scale basis. This appears, on balance, unlikely to occur on a regional basis in the short-term and while Alliance-wide ASW exercises conducted elsewhere can provide some corporate-knowledge, the specific characteristics of ASW differ by region. The alliances most viable pathway to constraining the Black Sea Fleet’s submarines runs through the emergence of Turkey as an actor capable of providing theatre ASW capabilities within the region.

Conclusion

While it may be tempting for naval strategists to write-off Russia’s capabilities in the Black Sea and focus heavily on threats to the North, the region retains both strategic and military significance. Members of NATO such as the UK should thus think in terms of a long-term campaign to constrain the Russian Black Sea Fleet’s freedom of action. This will involve working with partners including Ukraine but increasingly, Turkey.

A more credible post-war Ukrainian navy built around a limited flotilla of MCM vessels and patrol ships to constrain grey-zone blockades will be vital to ensuring that the Black Sea Fleet cannot militarily support a commercial strategy for the emergence of Russia as a monopolistic provider of food in key regions. In a conflict, Ukrainian anti-access capabilities can contribute to limiting the Black Sea Fleet’s freedom to operate. Equally, actors such as Turkey, have considerable strategic significance and it will be important to make the best of a likely Russo-Turkish duopoly in the region by bolstering Turkey’s ability to emerge as the dominant actor.

© RUSI, 2025.

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