The war in Ukraine has turned the Black Sea into a theater of unprecedented tactical and strategic transformation. For the first time, a country without a full-fledged conventional navy has managed to seriously shake and partially neutralize the dominant Russian flotilla in the region. This is one of the main conclusions of a large-scale military-strategic analysis based on verified British intelligence data, independent OSINT platforms like "Oryx," and specialized defense research.
One-third of the Russian Black Sea Fleet out of action
According to confirmed data as of mid-2026, about one-third of the original composition of the Russian Black Sea Fleet has been sunk or rendered inoperable with no real possibility of recovery. Among the dozens of affected vessels are strategic assets whose loss seriously limits Moscow's ability to project and use military force in the Black Sea region.
The most iconic strike remains the sinking of the flagship – the missile cruiser "Moskva" – in April 2022, which deprived the Russian flotilla of a key element of its air defense. Another serious blow was the destruction in September 2023 of the Kilo-class submarine "Rostov-on-Don" in a dry dock in Sevastopol – the first loss of a Russian submarine since World War II.
Russian amphibious capacity has been practically paralyzed following the destruction of large landing ships such as the "Saratov," "Minsk," "Novocherkassk," and "Caesar Kunikov." Among the lost or incapacitated vessels are also modern patrol units like the "Sergey Kotov" and "Ivanovets." Thus, the Russian capacity for amphibious operations and control over maritime communications has been significantly restricted.
Asymmetric maritime warfare has rewritten the rules
Kyiv's naval success rests on an innovative asymmetric doctrine built on three key components. The first is the massive use of uncrewed surface vessels (USVs) like "Magura V5" and "Sea Baby," which allow for strikes without the need for a traditional large naval fleet.
These drones are combined with precision strikes using Western cruise missiles on fortified infrastructure targets in Sevastopol and Kerch, which further erodes Russia's ability to maintain safe bases for its fleet. The third component is access to real-time intelligence provided by Western strategic "RQ-4 Global Hawk" drones, which patrol in international airspace.
Under this constant pressure, the Russian command was forced to withdraw some of its most valuable naval assets from Crimea to the perceived safer port of Novorossiysk. The retreat allowed Ukraine to unblock some of its own ports and build a functioning unilateral "grain corridor" that passes through the territorial waters of Romania and Bulgaria.
Turkey, Romania, and Bulgaria: new security doctrines
The three Black Sea NATO member states – Turkey, Romania, and Bulgaria – have adapted their national doctrines to the new security environment, seeking a balance between their own interests and commitments to the Alliance. The most visible result of this cooperation is the creation of the joint mine-countermeasures naval group "MCM Black Sea." The initiative of Ankara, Bucharest, and Sofia aims to ensure the safety of navigation by detecting and neutralizing drifting sea mines.
In parallel, Turkey, Romania, and Bulgaria have strengthened the monitoring of their air and maritime space, as well as control within their own territorial waters and exclusive economic zones. The Black Sea region has become a testing ground for joint operations, modernized flotillas, and coordination within NATO.
Turkey – the guardian of the straits
Ankara has maintained its specific role in the region through the strict implementation of the 1936 Montreux Convention. The closure of the Bosphorus and Dardanelles to warships prevented Russia from reinforcing its Black Sea Fleet with additional units from other theaters. At the same time, this measure also limited access to the Black Sea for warships from other NATO member states.
Turkey has continued to supply strategic weaponry to Kyiv – including drones – but has maintained distance from Western sanctions regimes against Moscow. Thus, Ankara combines its role as a NATO ally with the ambition to remain a key mediator and an independent factor in regional security.
Romania – the most proactive player on the eastern flank
Bucharest has taken the most active position among the Black Sea states on the eastern flank, viewing the war in Ukraine as an immediate threat to its national security. Concerns intensified after a series of incidents involving Russian drones falling near Romanian territory along the Danube.
The port of Constanța has become a vital route for Ukrainian exports, especially grain, which passes through the new corridor via Romania and Bulgaria. In parallel, Romania has invested billions in the expansion of the "Mihail Kogălniceanu" airbase, which is gradually becoming one of the largest and most strategically important NATO bases in Europe.
Bulgaria – military aid and energy diversification
After a period of internal political consolidation, Sofia integrated firmly into the common Euro-Atlantic response to the war. Bulgaria played an important role by providing large-scale military-technical aid to Kyiv, including Soviet-caliber ammunition and armored vehicles, which are key to Ukrainian operations.
Simultaneously, the country strengthened control in its exclusive economic zone in the Black Sea, including in terms of navigational safety and potential hybrid threats. Among the most significant strategic changes is the achieved energy diversification – the breaking of long-standing dependence on Russian natural gas and nuclear fuel, which reduces Bulgaria's vulnerability to energy pressure and places the Black Sea in a new context of security and economic interests.