Romania, Bulgaria and Turkey in the Black Sea region: more cooperation?

The full-scale invasion of the Russian Federation (FR) into Ukraine increased the risks to the safety of allies in the Black Sea region – Romania, Bulgaria and Turkey. These countries have different perceptions of the challenges and threats and, until recently, how to respond to them. Romania considers Moscow a major military threat and has been seeking to "internationalise" the safety of the Black Sea for years. Bulgaria, which formally recognised the FR threat as a fact after 2022, seems to be the most passive ally. Turkey sees it as a challenge (not giving up on the possible of bilateral economical cooperation), but not a direct threat. She engaged in military activities in another strategical directions and was reluctant to importantly increase NATO's presence in the neighbourhood.

It was only in 2024 that, due to a common interest in combating maritime mines limiting the safety of shipping in the Black Sea, the 3 countries undertook a tripartite military cooperation. NATO's adoption of the regional defence plan for South Europe in 2023 should theoretically strengthen this cooperation, but in practice this has not yet been demonstrated.

Romania, Bulgaria and Turkey, however, will gotta adapt their policies to fresh challenges: a possible simplification of the United States' military presence in the region, concerns about the way the war ended in Ukraine and further improvement of Russian military potential. These countries are awaiting greater work for defending and deterring in this part of the continent in working with Western European allies, replacing the U.S. commitment. This will require faster and more crucial investments in its own military potential, as well as strengthening regional cooperation.

Different views on regional security

Romania considers the Black Sea a key area for its safety and economical interests,and FR – for the basic threat on this watershed. This position was reinforced by the invasion of Ukraine in 2022 and earlier by the annexation of Crimea in 2014, after which the actual distance between the borders of both states had been de facto shortened from 500 to 200 km, and the main Romanian air force base under Constance was within scope of Russian anti-aircraft and rocket systems deployed on the seized peninsula. The Black Sea is besides fundamental to home trade and energy. Romania has the largest seaport (Constanca) on its waterfront and is operating, so far on a tiny scale, natural gas resources in its offshore exclusive economical region (WSE).

The intention of Moscow after 2022 to gain control of the Ode Ode circuit raises concerns in Bucharest that it may besides gain access to the mouth of the Danube in the future and block this delicate communication artery for local trade. In addition, Romania sees Russia as the main opponent in competing for influence in Moldova^[1]. Realizing the limited capacity to plan forces in the Black Sea basin, especially in its waters, it is so seeking to internationalise regional safety issues. This means expanding the presence of allied forces, especially in maritime and air domains.

For Bulgaria The Black Sea is an crucial area primarily in the economical context, first for the tourism sector, which generated almost 7% of its GDP in 2023. For years, Sofia had not seen a military threat in the FR, and subsequent governments attempted to keep a good relation with Moscow, the basis of which lay historical and cultural ties. The change was only brought by a full-scale invasion of Ukraine, which prompted Bulgaria, among others, to accelerate the modernisation of the armed forces, including those to defend the coast. Political elites stay divided on the issue of hazard assessment by Russia, but strategical papers specified as National Defence Strategy of 2025^[2]They identify her as the main threat to the state. Political instability (seven installments of parliamentary elections since 2021) limits Sofia's ability to formulate an effective consequence to changing regional safety conditions.

Russian activities in the Black Sea besides hit local energy projects, involving the exploitation of Black Sea natural gas resources located in the Bulgarian WSE. In 2023, the FR blocked access to it under the pretext of conducting naval military exercises, which Sofia considered a provocation.

Black Sea strategy Turkey It fits into her policy of balancing between Russia and the West. Ankara wants to avoid a military escalation that could lead to a war between NATO and the FR, and thus the hazard of bringing it itself into armed conflict on this watershed. At present, it sees no direct military threat from Russia, but considers it a competitor in the neighbourhood. The possible end of the war to the detriment of Ukraine and the possible seizure of its south-western part are causing concern in Turkey about the increase in the military dominance of the Kremlin. The blockade of the Black Sea Straits by Ankara in February 2022 – under the Montreux Convention^[3], for both fighting states (Russia and Ukraine) – prevented the FR from strengthening its fleet on this watershed.

Ankara seeks to keep the current power strategy in the Black Sea and remains reluctant to increase NATO's maritime presence in its area. For Turkish authorities, despite their wider rivalry with Moscow in the South Caucasus, Libya and, until recently, Syria, FR is inactive an crucial economical and energy partner. Avoiding armed escalation in the region besides allows the Turkish Navy to focus more attention and resources on the mediate East and Africa, where Ankara seeks to maximise its political, economical and military influence. The Turkish Navy is present in Libya, Somalia or Qatar, alongside its permanent presence in the Turkish WSE in the Mediterranean and Aegean. In the event of a conflict in the Black Sea region, Ankara would request to strengthen its forces in this direction, limiting military engagement in another parts of the world.

Military possible and modernisation priorities

Romania and Bulgaria are developing armed forces as part of NATO's defence planning to deter and defend Russia's possible aggressive moves towards the Alliance. Both countries, due to financial constraints, focus primarily on air and land forces and to a lesser degree on the Navy. In turn Turkey does not see itself as a state of the east flank of NATO and is expanding its military possible not only in an allied context. He has a second-largest army in the Alliance, and its modernisation and reforms reflect the ambitions of active and multi-vector abroad and safety policy. Land troops there operate in the territories of confederate neighbours (in Syria and Iraq) against a Kurdish terrorist organisationPKK and its affiliated groups. Turkey balances between the pursuit of a "strategic autonomy" in the political-military area and the obligations arising from NATO membership, which periodically creates crises in relations with allies.

Defence expenditure Romania (whose army has various sources from about 66,000 to about 80,000 active-duty soldiers) ranged from 1.35% to 1.84% of GDP between 2014 and 2019. The 2% of GDP ceiling has only achieved twice so far – for the first time in 2020 and then in 2024 (from 2021 to 2023 the budget of the Ministry of Defence was around 1.7%). Bucharest focuses on the improvement of air force (purchase of 4th and 5th generation F-16 and F-35) fighters^[4] and intensive modernization of land troops (armoured transport, tanks, artillery)^[5]. He besides invests in the acquisition of Patriot mid-range air defence systems^[6] and coastal defence systems designed to destruct marine targets from land utilizing missiles NSM^[7]. Naval improvement has not yet been considered a priority, so its possible remains limited. Among the crucial objectives of Bucharest is to keep the safety and low costs of commercial shipping in the Black Sea. After the largest threat to its safety from 2022 became drifting Russian and Ukrainian mines, Romania, with its low capacity for neutralisation by 2022, decided to get 2 utilized mine destroyers. In 2025, however, it initiated a procedure for purchasing Corvette and the authorities declare further investments^[8].

Bulgaria Over the years, it has spent 1.3-1.5% of GDP for military purposes (except for 2019 erstwhile it was 3.1% of GDP in connection with the acquisition of F-16). After 2022, however, it increased its defence spending, reaching 2.04% of GDP in 2024. The number of her army (depending on sources) is 25–33 1000 soldiers in active service. At the same time, Sofia has taken steps to modernise the armed forces and to become independent of Russian supplies of parts to its still-exploited russian military equipment. This effort gradually includes the Navy and air defence systems, but long-term negligence in these areas makes it impossible to clearly improve the situation in the short term. Flag military investments mainly concern the air force – acquisition of F-16 fighters^[9] and short-range IRIS-T SLM air defence systems^[10].Sofia's precedence in the Black Sea is to fight against mined waters.

The Bulgarian Navy has a fleet of obsolete units with tiny combat capabilities. Between 2023 and 2024 2 patrols were launched in Varna to be equipped with Swedish RBS-15 anti-ship missiles. They will enter service in 2025 and 2027 respectively. On the another hand, the decision to acquisition fresh missiles for coastal defence systems on land (the NSM or RBS-15 is considered).

Turkey Before 2022, it spent only 1.3-1.85% of GDP on defence, which was mainly due to economical problems, but in 2024 it had already invested 2.09% of GDP. AnkaraFor years, it has implemented a comprehensive programme of modernisation of the army combined with the construction of a defence manufacture capable of producing key weapons and military equipment for all types of armed forces of the state and for export. As part of this process, it improves its air force, including F-16 fighters (about 150 out of 236 and plans to acquisition 49 fresh ones), and seeks their successor^[11]. In the long term, it develops its own TF KAAN fighter which aspires to be a 5th generation machine. The Turkish air force has an extended and advanced fleet of unmanned aircraft, and uses a variety of their own platforms to manufacture them. On the another hand, a generational replacement of combat vehicles (Altay tanks, Kirpi armoured vehicles, Kaplan and Pars, Haubice T-155 Fırtına and unmanned land vehicles) is taking place in land troops (approximately 355 1000 soldiers in active service). The Navy is developing the MILGEM program, comprising the corvettes of home Ada-type production and the frigates with Atmaca anti-ship missiles, besides implemented the TCG Anadol landing ship for service, which was intended to service F-35B fighters. Due to the exclusion from the F-35 programme, the State's aviation component is presently limited only to unmanned workers. Turkey besides plans to build its own submarineunder the MILDEN programme. Turkey's air defence is based on a large number of old HAWK and Rapier short-range systems, but is to be replaced by native HİSAR and SIPER short-range systems^[12]. Ankara besides develops its own short-range ballistic missiles (Bora) and maneuvering missiles (Çakır).

NATO and trilateral military cooperation in the region

Allied activity in the Black Sea region following Romania and Bulgaria's accession to NATO in 2004 was mainly to usage their military bases to support the securing of United States operations in the mediate East and Africa. In 2010, the U.S. Marine Corps' rotational presence began in both countries and in 2014 the U.S. rocket strategy Aegis Ashore was launched in Romanian Devesel, part of the NATO rocket defence system^[13].

Despite the strong efforts of the Romanians, however, after 2014 it was not possible to establish a black sea crew of ships or to guarantee the permanent rotational presence of allied combat groups in its territory – NATO decided to place only a tiny training mission there^[14]. The mission of enhanced supervision of Romanian and Bulgarian airspace has been launched. W from 2014 to 2020, British and U.S. Navy destroyers each year conducted exercises to guarantee freedom of navigation in the Black Sea, consisting of joint patrols with Turkish, Romanian and Bulgarian units, visited the port of Odessa and flowed through Crimean territorial waters. In 2022 NATO importantly increased its presence in the region. Appointed cNew conflict groups^[15] – France became the Framework State in Romania^[16]in Bulgaria, Italy. In 2023 the Black Sea area was covered by the Alliance's fresh regional defence plan, including South Europe, the Mediterranean and Turkey.

In fresh decades, the United States has been the most active in strengthening safety in the Black Sea basin. Their presence is concentrated in Romania, where about 1.8 1000 U.S. Army soldiers are stationed (the infantry brigade; between 2022 and 1923 this number reached 3 thousand). Since the end of 2021, American reconnaissance, reconnaissance and command aircraft and unmanned aircraft have maintained almost constant activity over water waters. The largest global military exercise in the region is the American Saber Guardian held all 2 years as part of wider DEFENDER Europe maneuvers. More than 2.4 1000 soldiers from the United States and 7.3 1000 from another countries (including Romania, Bulgaria, France and Italy) participated in the 2023 edition.^[17].

Romania has for years sought to grow the U.S. military presence and allies in this part of the world^[18]. More pAt the 2016 NATO Summit in Warsaw, it launched initiatives (without success) on the stationing of its land troops and the creation of the Black Sea Fleet. Before 2022. Turkey and Bulgaria remained skeptical of them, fearing a deterioration in relations with Russia and an increase in tension in the neighbourhood. DHowever, statements of war in Ukraine convinced Sofia to increase the Alliance's commitment. Turkey besides did not argue its land presence in Romania and Bulgaria and supported its defence plans for the region. As the strongest military ally in it besides became active in mission of enhanced airspace surveillance of both countries and belongs to the NATO Combat Group in Bulgaria with about 200 soldiers. However, in fear of exacerbating Ankara's situation, it systematically stressed the necessity of avoiding escalation and maintaining dialog with the FR, and stressed compliance with the Montreux Convention, which limits the presence of allied forces on this approach.^[19].

Before the Russian invasion of Ukraine Turkey, Romania and Bulgaria participated in multilateral formats of military cooperation in the Black Sea basin. The land domain included (including Greece and Italy) as part of the South East European Brigade (SEEBREG), promoting regional cooperation and interoperability. In the maritime domain, along with another coastal states (including Russia and Ukraine) from the beginning of this century, they had been part of the Black Sea Naval Force forces and participated in Operation Black Sea Harmony to counter terrorism and asymmetric threats to water. However, these initiatives ceased to function after 2014, and only full-scale FR aggression to Ukraine initiated the tripartite cooperation of the Black Sea Allied States. In 2024, a Turkish-Bulgarian-Romanian antimine task force of the MCM Black Sea (Mine Countermeasures Black Sea Task Group) was launched, whose task is to destruct the risks to maritime safety in the Black Sea created by drifting mines.

What about deterrence and defence in the region?

Russia's invasion and territorial conquest strengthen Moscow's military position in the Black Sea basin. The creation of a land corridor to Crimea through the seizure of parts of the Ukrainian Kherson, Zaporosian and Donetsk districts facilitated the maintenance and securing of logistical formations operating from the peninsula. Thus its power projection capabilities in air and sea domains have increased. possible further conquests of oversea areas will not have much impact on Moscow's regional possible in these domains. The business and further militarisation (building of reconnaissance and impact systems) of the Ukrainian Snake Island in the Black Sea would be peculiarly problematic due to its location close to the Romanian coast. The establishment of the Russian-Romanian land border – although presently improbable – would represent a diametric change from Bucharest and the full NATO perspective.

Proposed by Donald Trump's administration, the possible simplification of US military presence in Europe may have consequences for the Black Sea basin, and especially for Romania. The question of maintaining American engagement in the region in terms of reconnaissance, reconnaissance, oversight and air command – especially for the needs of Kiev, but besides the full Alliance – remains open. Consequently, and due to many uncertainties about the end of the war in Ukraine and the further expansion of Russian military potential, the Black Sea states of NATO will gotta (in cooperation with European allies) presume greater work for defence and deterrence in the region. This means faster and increasing investments in both modernisation and capacity building and in cooperation with neighbours.

Romania should be curious in the effective implementation of ongoing programmes for the improvement of coastal defence systems and aviation potential. In the worst case scenario, Bucharest would not only gotta accelerate the modernisation of land troops but besides increase their numbers. He will besides gotta consider raising the possible of the Navy – it seems reasonable to return to the thought of gaining at least 2 fresh corvettes abandoned in 2023. Moreover, the request to strengthen (quantitative and qualitative) their marine capabilities will shortly become increasingly urgent due to planned energy projects, requiring military protection^[20]. Furthermore, the possible simplification of US presence in the region will translate into an increase in France's engagement in Romania.

In the interest of Bulgaria lies the further modernisation of land and air forces. Given the unstable interior political situation^[21] and the material difficulties of Sofia's policies in strengthening regional safety are hard to predict, but it is likely to take a reactive stance, adapting to the actions of the larger players in the neighbourhood. The continuation of the war or Moscow triumph may, however, force Bulgaria to transfer part of the funds to underfunded Navy to better safe energy infrastructure in the Black Sea^[22]. Due to budgetary constraints, Bucharest and Sofia will not make importantly and rapidly the possible in the field of aviation and, consequently, will be forced to trust on allies, including Ankara.

Turkey it is the only NATO country in the Black Sea Region with the possible of completing capacity gaps in the air and maritime domains to leave behind the retreating forces of the US, although this would require investment and expansion. The end of the war in Ukraine in favour of the aggressor would besides be a challenge for Ankara, as Russia would most likely increase military presence in the Black Sea basin. In the event of an exacerbated situation in the region, Turkey would most likely be ready to increase the engagement of its own naval and air forces. However, this would mean both redirecting military resources from another strategical directions, as well as reviewing its position in the Black Sea basin and, in part, balancing policy between NATO and Moscow. At the same time, not only due to the desire to avoid confrontation, but besides due to extended energy cooperation with FR (gas import and cooperation in atomic energy) Ankara will search to prevent possible escalation.

Romania, Bulgaria and Turkey will gotta step up their cooperation in the Black Sea basin under NATO, implementing the commitments of the local defence plan, including the Black Sea. This should translate into more training and exercises involving, among others, these 3 countries and a two- and three-way approximation. It would be reasonable to set up a joint (located in Constance, Varna or Istanbul) centre for coordination of actions or crisis consequence that would monitor movement on water, exchange of data and respond to incidents – like the Command Task Force Baltic (CTF Baltic) operating in the Baltic. The EU can besides become a safety support platform for Black Sea. W On May 2025, the European Commission, together with the advanced typical for abroad Affairs and safety Policy, announced a fresh strategy for the region, which includes the establishment of the Black Sea Maritime safety Hub. This initiative aims not only at strengthening maritime safety, but besides at protecting critical infrastructure by real-time information exchange, monitoring threats and coordinating mine-based actions.^[23].

Map. Military and maritime infrastructure in the Black Sea region

Source: own development.