This chapter outlines the key priorities to guide Europe’s regional strategy for the Black Sea and highlights how these actions can reinforce its diplomatic role in ending the war. Given the Black Sea’s central role in any future path towards peace, and in preventing the emergence of further conflicts, achieving a minimum level of stability is essential.

Europe can contribute in three ways: a) investing in Ukraine’s defence and maritime sectors to ensure that Ukraine maintains access to the Black Sea and that its key ports, like Odesa, remain operational; b) reducing political and economic vulnerabilities in Black Sea states, including countries like Moldova, Bulgaria and Georgia, to limit exposure to hybrid threats; and c) building deterrence for the security of the littoral states by improving connectivity, enhancing support, and deepening trilateral cooperation among NATO’s Black Sea members – Romania, Bulgaria and Türkiye. The presence of a coordinated maritime framework is equally important, both to monitor ceasefires and to safeguard commercial navigation while countering hybrid threats.

4.1 Ensuring Ukraine maintains access to the Black Sea

Russia’s war on Ukraine remains the Black Sea’s most urgent source of instability. The war’s outcome will shape the security of all littoral states, and the risks for them will increase sharply if Ukraine’s position weakens. As Moscow shows no willingness to negotiate or halt attacks, preserving Ukraine’s access to its Black Sea ports and EEZ is critical. If Russia were to sever Ukraine’s maritime access or occupy more of its adjacent coastline, it would undermine Kyiv’s economic viability, drain its coffers and alter the region’s broader balance of power. Control of Ukraine’s southern coast would also create a direct land corridor to Transnistria, while bringing Russian military assets closer to NATO territory. This would position Moscow to deploy certain types of weapons from a shorter distance against Romania, Bulgaria, and other NATO members, further heightening regional insecurity.

Ensuring lasting access to the Black Sea demands a multifaceted approach. First, any ceasefire or eventual peace agreement must explicitly guarantee Ukraine’s right to operate its Black Sea ports – especially Odesa – and include long-term (deterrence) measures to prevent renewed Russian aggression. Without such provisions, Moscow could regroup and again attempt to choke Ukraine’s maritime lifeline.

Second, military and technological support is central to this goal. Ukraine has successfully denied Russia control over large parts of the Black Sea. Since regaining control of Snake Island, the Boyko towers, and much of its territorial waters,[26] Kyiv has reshaped the Black Sea’s security dynamics. However, it has struggled to sustain the level of USV (unmanned surface vessel) and UAV (unmanned aerial vehicle) attacks required to push the Russian navy further back and to curb air- and missile-based strikes on Ukrainian seaport infrastructure. As a result, Russia retains the capability to strike Ukraine’s maritime assets and continues to threaten Ukrainian exports overseas through missile attacks and the potential obstruction of shipping routes. Meanwhile, maritime tactics on both sides continue to evolve rapidly as innovation accelerates.[27] Continuous funding for domestic research, the production and rapid adaptation of naval and submarine drones, along with expanded payload capacity, are crucial to sustain Ukraine’s edge. Equally important is a steady supply of modern anti-air missile systems to protect port infrastructure, shipyards, and critical defence-industry facilities from aerial and missile attacks.

Third, economic resilience complements military strength. Ukraine’s defence effort depends on a robust economy and access to capital, supply chains, and export markets. Deeper EU integration, through trade facilitation, infrastructure links, and regulatory alignment, would strengthen these connections. The lapse of the EU’s Autonomous Trade Measures (ATM) in mid-2025[28], along with the EU’s delay in opening the first “Fundamentals” chapter of accession negotiations, constrains export revenues and delays needed reforms. Accelerating these processes, extending the Trans-European Transport Network (TEN-T), and supporting reconstruction loans from the EIB (European Investment Bank) and EBRD (European Bank for Reconstruction and Development) would help to sustain Ukraine’s economic strength and recovery.

Finally, after a ceasefire, coordinated Black Sea monitoring and patrol missions by third parties will be needed to enforce maritime security. Given Russia’s unchanged strategic ambitions, such missions must consist of or be backed by credible deterrence capabilities and demining efforts. Security guarantees at sea - whether through NATO arrangements, EU initiatives, or a dedicated maritime coalition - will be essential to deter further Russian incursions and protect Ukraine as well as other littoral states.

4.2 Reducing the dependencies and vulnerabilities of the littoral states

Regional stability depends not only on deterrence against Russian hybrid threats but also on identifying and addressing vulnerabilities that could be exploited through hybrid warfare. While every state in the Black Sea region has weak spots, this report focuses on those most susceptible to exploitation through hybrid warfare. Situated at the crossroads of strategic routes, these countries face both economic opportunities and external pressures, which can limit their freedom to shape independent foreign policies. Yet, with proper development and support, their untapped economic potential could strengthen regional deterrence.

Moldova

Moldova, though not a littoral state, illustrates this point well. Positioned as a transit country between Romania and Ukraine, the war has nearly dried up trade with Ukraine, one of its most important trading partners.[29] However, its infrastructure – roads, rail, and the small port of Giurgiulești – already helps to reroute Ukrainian exports. The EU’s “Solidarity Lanes” highlighted Moldova’s role when small Danube ports like Izmail became critical for grain shipments.[30] The future reconstruction of Ukraine will only increase Moldova’s strategic relevance, provided that EU investments in border improvements and connectivity with Romania reduce bottlenecks and tie it more firmly into European supply chains.

Russia’s invasion of Ukraine has turned Moldova into a strategic vulnerability for the EU. Moscow’s military presence in Transnitria, a narrow strip of land in the east, bordering Ukraine, Transnistria, and disinformation campaigns seek to destabilise the country’s pro-European government. However, the outcome of the recent parliamentary elections has demonstrated growing resilience against these efforts.[31] A pro-Russian shift in Chișinău could threaten Odesa and southern Ukraine, while complicating Moldova’s EU trajectory. Conditioning accession on Russian withdrawal risks granting Moscow a veto, but ignoring the issue raises doubts about Moldova’s viability as a sovereign EU member. Transnistria’s economy has collapsed after losing Russian gas subsidies, with industrial output down by over 50%.[32] This raises questions about the region’s future and possible reintegration. Such a process would demand political will in Chișinău and a clear EU strategy with sufficient funding, providing measures to address socio-economic pressures and ensure broad societal acceptance.

Another aspect of vulnerability is connected to Moldova’s public perception of its declared neutrality and weak defence posture. Public opinion often favours disarmament to avoid provoking Russia, leaving the responsibility for its deterrence to neighbouring Romania, even though Moldova has increasingly been a target of Russian hybrid threats, cyberattacks, and disinformation in recent years.[34] Many Moldovans rank the erosion of traditional values higher than the risk of military aggression.[35] This illustrates a gap between perception and reality – one that Russia exploits through disinformation. A broader societal shift is required: defence must be seen as a shared responsibility, not just external protection.

Bulgaria

Despite external threats, internal vulnerabilities may be equally destabilising. This is also the case for Bulgaria. Until recently, Moscow regarded Bulgaria as its most reliable partner in the European Union, largely due to Russia’s grip on Bulgaria’s energy sector, sympathetic political elites, and historical links that allowed Moscow to influence public opinion through disinformation. Long-term Gazprom contracts, the $1.59 billion TurkStream extension, and strategic corruption gave Russia major leverage.[36] The 2022 Russian invasion of Ukraine changed this dynamic. Bulgaria condemned the invasion, declared Russia a threat to its national security, aligned with EU sanctions, expelled Russian diplomats, arrested officers for espionage, and provided military support to Ukraine. Moscow retaliated by cutting 90 percent of Bulgaria’s gas supply and launching cyberattacks on its energy infrastructure.[37]

Having joined Schengen in 2024 and aiming for Eurozone entry in January 2026, with OECD membership as a long-term goal, Bulgaria maintains a clear pro-Western course. Nonetheless, Russian disinformation continues to resonate, with public opinion on Eurozone accession being evenly divided. Meanwhile, some political actors with vested ties to Moscow have undermined political stability, resulting in seven parliamentary elections over three years.[38]

Bulgaria nonetheless holds notable potential as a regional security contributor, particularly through its defence sector. Once the Warsaw Pact’s main ammunition producer, Bulgaria’s defence industry has grown by 200% since 2022, quietly becoming one of Ukraine’s largest suppliers in the region.[39] Revenues from ammunition sales are used to modernise outdated capabilities, and plans are underway for drone production, new patrol vessels, and upgrades to the naval base in Varna to support NATO operations. Yet foreign investors remain cautious due to political volatility and doubts over whether funds will be properly managed.

Sofia remains committed to regional security. Beyond its role in the joint mine-countermeasure taskforce with Romania and Türkiye, supported by the Netherlands and Belgium, Bulgaria is seeking a larger role. Prime Minister Rosen Zhelyazkov recently proposed hosting a multinational maritime coordination centre in the western Black Sea. The centre would focus on surveillance, intelligence-sharing, and protecting undersea infrastructure, that could also help in monitoring a potential ceasefire.

To unlock its potential as a regional security contributor, several steps are important. First, more political attention from Brussels could help counter Russia’s efforts to cast doubt within Bulgarian public opinion about ongoing reforms. Second, Bulgaria’s own security contributions deserve recognition. While the EU’s support for regional initiatives is valuable, priority should be given to strengthening local capacities, including the maritime domain or intelligence, surveillance, and reconnaissance (ISR) assets. Third, Bulgaria has the capacity to expand arms manufacturing to help NATO replenish ammunition stockpiles. However, domestic caution about raising its military profile, meant to avoid provoking Russia, has slowed progress. Despite this, the defence industry remains socio-economically important, employing more people proportionally than in many other EU countries. Bulgaria is also an important candidate for EU investment in dual-use infrastructure in the region, as outlined in the EU Black Sea Strategy.

Georgia

Once a promising EU partner and reform frontrunner, with visa liberalisation and NATO- and EU-backed defence cooperation and investments, Georgia now shows little appetite for accession, having suspended the EU accession process until 2028. The European Council had already noted in its June 2024 Conclusions that Georgia’s accession trajectory had been de facto halted.[40] European engagement has been eclipsed by growing trade with Russia after Western sanctions[41] and exploratory deals with China. Georgia’s GDP grew by 7.8% in 2023 and 9.4% in 2024.[42] According to official data the EU remains Georgia’s largest trading partner at 22.1% of total trade,[43] yet Kyrgyzstan has become the single largest export destination, likely through vehicle re-exports to Russia,[44] underlining how much the country has moved eastward. While framed as prudence to avoid provoking Russia, the Georgian Dream’s approach primarily advances the ruling elite’s economic interests and risks weakening Georgia’s ability to maintain sovereignty over its foreign policy in the future.

For the EU, Georgia matters most in the Black Sea and Middle Corridor context, with the Global Gateway flagship initiative, the 1,195-kilometre Black Sea Submarine Cable (BSSC), connecting Azerbaijan, Georgia, Romania, and Hungary to diversify Europe’s green energy imports,[45] and the Anaklia Deep Sea Port, intended to anchor Georgia in European trade routes.[46] A Chinese-Singaporean consortium now leads the Anaklia development after European bids were dismissed as unviable. The Western private sector, from Belgian dredgers to Dutch logistics companies, remains interested but cautious. APM Terminals could expand operations, but uncertainty and political opacity deter broader investment. In the meantime, logistical bottlenecks in the Middle Corridor – outdated infrastructure, inadequate warehousing, slow digitalisation – remain unresolved. These are precisely the areas where European firms could contribute, yet the government prefers short-term deals that maximise autonomy.

While high-level dialogue has been suspended since mid-2024,[48] some of the defence and security matters remain exempt. The country continues to host the EU Monitoring Mission (EUMM) along the boundaries with Abkhazia and South Ossetia and remains a NATO partner under the Substantial Package. However, Georgia is no longer a reliable partner on sanctions, cyber cooperation, or intelligence sharing.

EU candidate status remains Brussels’ strongest anchor, but the government shows little interest in fulfilling its obligations, and conditionality tied to reforms has lost its effect. Still, the EU cannot completely disengage. Georgia’s geographic position makes it key for Black Sea security, energy transit and sanctions enforcement. A return to values-based conditionality is unlikely to work in the current climate. Further disengagement would allow Moscow and Beijing to shape the region’s economic and political landscape at Europe’s expense.

The alternative is to maintain limited engagement where EU policy permits, while avoiding gestures that could be interpreted as political endorsement. Progress towards EU integration should continue to be assessed on a merit-based basis. This approach could be complemented by engagement with Georgia through individual member states rather than Brussels alone. Romania – with its strategic partnership with both Azerbaijan and Georgia – alongside Sweden and Poland, the initiators of the Eastern Partnership, could serve as credible intermediaries to maintain dialogue and influence.

4.3 Strengthening regional deterrence through a maritime coordination mechanism

When it comes to strengthening the deterrence of littoral states against hybrid threats from hostile state actors in the Black Sea, several challenges are best addressed at the regional level. These include vulnerabilities in critical energy and transport infrastructure, the lack of a comprehensive mapping of strategic assets, and continued dependence on U.S.-led intelligence networks.

Romania

This is visible in Romania, which has consistently been the most proactive NATO littoral state in advocating for deeper NATO and EU engagement in the Black Sea. Its urgency reflects intertwined security and economic concerns. Since Russia’s 2014 annexation of Crimea, Romania’s key air base and other military assets near Constanța have been within range of Russian air-defence and missile systems, while Moscow’s ambitions to gain land access to Moldova threaten to expand its influence over a country that Bucharest considers strategically vital. Russia’s military activities also endanger commercial shipping, as drifting sea mines from military operations since 2022 have increased costs and risks for Romania’s trade. Equally important, Romania seeks to protect its offshore natural gas resources, a pillar of its future energy independence.

Recognising its limited maritime deterrence, Romania aims to “internationalise” Black Sea security[49] by seeking active EU and NATO involvement, expanding regional infrastructure for military mobility, and investing in naval and mine-countermeasure capabilities. Romania’s defence policy has been coherent since joining NATO in 2004, aimed at transforming a conscript-heavy force and outdated equipment, much of it predating 1991, into a modern, downsized force integrated with NATO and the EU, a process accelerated after 2014 by larger defence budgets.[50] Romania hosts U.S. forces under a 2005 agreement,[51] contributes to NATO air policing over Romanian and Bulgarian airspace, and has welcomed four new NATO battlegroups since 2022. In 2023, the alliance incorporated the Black Sea into a regional defence plan, stationing about 1,800 U.S. Army soldiers—peaking at roughly 3,000 during 2022–23—while U.S. reconnaissance aircraft and drones have maintained an almost constant presence. This reflects Romania’s ambition to become a backbone of deterrence and regional resilience in the region.

Romania and Bulgaria have urged Brussels to adopt a strategic Black Sea approach, and President Nicușor Dan has offered to host a proposed EU Black Sea maritime security hub. Announced in May 2025, the hub aims to pool data on regional monitoring,[52] but its effectiveness will depend on strong intelligence, surveillance, and reconnaissance (ISR) capabilities. Romania has recently expanded its A2/AD capabilities, Bulgaria still operates with limited assets, and Türkiye currently supplies about 67% of the maritime situational picture.[53] Additional EU assistance, such as support for procuring corvettes, frigates, and other naval assets, could help close the remaining gaps.

Domestically, Bucharest is expanding its Mihail Kogălniceanu base, expected to become NATO’s largest European facility by the mid-2030s. Romania has also launched a corvette procurement programme and broadened mine-countermeasure capabilities. The Mine Countermeasure Black Sea Task Group, a trilateral Romanian-Bulgarian-Turkish effort which has been operational since early 2025, currently covers NATO members’ waters, but could be expanded to Ukrainian waters after a ceasefire, providing a broader patrol mission.

All in all, Romania has the potential to serve as a central pillar within the EU framework for deterrence and regional resilience in the Black Sea. For the EU, this implies prioritising the development of transport links between Romania, Bulgaria and Türkiye to improve military mobility and create secure corridors, drawing on NATO’s commitment to dedicate 1.5% of defence spending to dual-use infrastructure. Such investments would enhance regional connectivity and stimulate economic growth. Black Sea patrols could also be reinforced through the deployment of underwater drones, which offer faster and more cost-effective coverage than traditional corvettes or frigates, benefiting both Romania and Bulgaria. In addition, opportunities for closer cooperation with Ukraine on coordinated drone-patrolling operations merit further exploration.

Türkiye

Türkiye, as the region’s strongest NATO member and the actor with the greatest leverage over Russia in the Black Sea region, has both the ability and ambition to take a leading role in regional security cooperation. However, Ankara’s foreign policy priorities often diverge from those of the EU,[54] resulting in a strained relationship and limited progress towards an integrated Black Sea security framework for regional deterrence.

Türkiye’s strategy balances between East and West. On the one hand, Türkiye has confronted the Russian posture on multiple occasions,[55] maintains a strategic partnership agreement and defence industry cooperation with Ukraine and sustains good relations with Black Sea EU members. On the other hand, Türkiye does not fully comply with EU and US sanctions and, despite broader rivalries with Moscow in the South Caucasus, Libya, and Syria, views Russia primarily as an economic and energy partner and a competitor rather than a military threat, unlike Romania and Bulgaria. This calculation could shift if the war ends at Ukraine’s disadvantage, expanding Russia’s territorial footprint and raising the stakes for Türkiye.

In this context, Türkiye’s role in enforcing the Montreux Convention[56] is particularly important. To safeguard a regional maritime balance and protect Ukraine’s interests, the Straits would have to remain closed to all warships throughout the negotiation process and until a durable settlement is reached concerning the Ukrainian territories occupied by Russia.

President Zelensky’s recent endorsement[57] of Türkiye’s offer to assume a larger role in Ukraine’s security guarantees, particularly overseeing the maritime component,[58] underscores a shift in Ankara’s posture. Although Türkiye initially remained outside the early-2025 talks between Ukraine and selected EU-NATO members on deterrence support, it has signalled a growing willingness to be informed and involved. This reflects an evolution from Ankara’s earlier focus on UN-led negotiations and a UN-mandated ceasefire mission in the Black Sea. By declaring its readiness to join Ukraine’s security guarantees, Türkiye aims to reinforce its regional leadership, not only as a facilitator of Russia-Ukraine talks and Armenia-Azerbaijan talks,[59] but also as a NATO member and Western actor. Hosting next year’s NATO Summit further underscores this ambition and offers an opportunity to explore renewed EU-Türkiye cooperation. Working through individual EU member states that already maintain commercial and defence industry ties with Türkiye, such as Poland and Italy, might help to build momentum and mutual benefit.[60]

Without Türkiye’s capabilities, making the proposed EU Maritime Black Sea Security Hub fully functional will be difficult, as there is currently no comprehensive picture of activity in the region. For a regional monitoring and patrol mission to be effective, cooperation on sharing ISR data is essential. A detailed mapping of critical infrastructure – pipelines, radar facilities, seabed cables, and other key assets – is also needed to integrate regional security planning. This remains one of the most challenging tasks, given diverging strategic interests, the lack of trust, and a limited willingness to share sensitive intelligence.

4.4 Black Sea maritime coordination mechanism

The prospect of a Russia-Ukraine ceasefire has heightened the need for a coordinated regional monitoring mission and a reliable mechanism to verify compliance. For any ceasefire to hold, eyes on the Black Sea are crucial. Continuous monitoring is needed to discourage deniable acts, provide unbiased evidence to resolve disputes, and create a rapid-response mechanism for any incidents that might occur. It also discourages sabotage, the fourth step on the hybrid-warfare escalation ladder, by increasing the likelihood of detection.

Ceasefire monitoring needs to include a maritime force that is visible, has inherent and credible force and operates assets clearly linked to the mission of securing maritime infrastructure, including port facilities and key lines of communication. This force should be in direct contact with a regional maritime coordination centre representing all relevant parties to clarify incidents and reduce tensions before they escalate. A key factor is Türkiye’s authority over the Turkish Straits under the Montreux Convention, which affects the size and composition of any deployed maritime force.

A new ceasefire monitoring framework that builds on emerging and existing initiatives, such as the EU Maritime Security Hub and the Mine Countermeasure Black Sea Task Group, and actively links these initiatives to the extent possible, would enhance the collective security of all littoral states. Such a mission would have to integrate aircraft, UAVs, and ships, preferably from third-party nations acceptable for both Ukraine and Russia, work in coordination with the two belligerent nations and report to a joint coordination centre of the monitoring mission. Mine Countermeasures Vessels (MCMVs) are best suited for this: seaworthy, equipped for frequent route surveys, and devoid of any offensive capability, thereby reducing the risk of provoking either side. If threats arise, an air-defence frigate or destroyer could escort the MCMVs, provide a command platform, and manage air coordination without requiring a land base. While Black Sea states should ideally supply MCM units, their limited fleets mean that European partners will likely need to reinforce the mission. Together they can sustain an effective maritime monitoring operation.

Over 400 anchored and drifting automatic contact mines have been deployed by both Ukraine and Russia since 2022 to protect or prepare for attacks against port cities and disrupt each other’s sea-based military operations.[61] The presence of these mines has sharply increased regional insecurity due to surface vessel strikes, civilian deaths and rising insurance costs for maritime shipping.[62] NATO member states Bulgaria, Romania and Türkiye have joined forces in a coordinated effort to address this security hazard through the establishment of the Mine Countermeasures Task Group Black Sea (MCM Black Sea). Since July 2024, the operation has deployed demining ships, patrol vessels, helicopters and drones from the three states involved.[63] A mine countermeasures effort, both sweeping and hunting, is required to ensure sustained safety for shipping. Initial efforts should focus on surveying and clearing agreed shipping lanes, eventually expanding to remove the mine threat entirely.

Ceasefire monitoring must also be paired with credible deterrence. A Maritime Security Hub could function as a central pillar to track surface and subsurface activity, counter electronic warfare such as spoofing and jamming, and enable real-time intelligence sharing. Grounded in an assessment of current military capacity, EU capability targets, and required investments, such a hub would reinforce Europe’s resilience and reduce the risk of Russian infiltration or hybrid attacks undermining the mission.

This maritime focus must be embedded in a wider Black Sea strategy that aligns with EU efforts to enhance North-South connectivity, particularly the Baltic–Black Sea–Aegean corridor and Corridor 8 linking the Black Sea to the Adriatic.[64] These routes require a military dimension, particularly an expanded rail capacity, to allow rapid reinforcement of NATO’s eastern flank. The current infrastructure cannot support large-scale troop movements without significant U.S. assistance,[65] while funding for upgrades remains uncertain.

Coordinated investment planning among the littoral states, the EU, and NATO is therefore essential to identify and finance priority projects that advance both economic and defence objectives and align with the EU’s broader strategic vision for the region.