In the four years that have passed since Russia annexed Crimea, the number of Russian submarines active in the Black Sea has grown from one to seven. These submarines pose a grave threat to the security of the North Atlantic Treaty Organization’s (NATO) eastern flank. And together with the Kremlin’s military buildup on the occupied peninsula, they have shifted the balance of forces in the region in Russia’s favor.

Immediately after the annexation of Crimea, Russia embarked on an ambitious program of modernizing its Black Sea Fleet, based out of Sevastopol. Originally, six Admiral Grigorovich–class (Project 11356P/M) guided-missile frigates and six Kilo-class submarines were to be constructed and deployed in the Black Sea (Interfax, May 13, 2014). Both frigates and submarines are capable of launching Kalibr land-attack cruise missiles with a range of over 2,000 kilometers. However, the ongoing war in eastern Ukraine has delayed the building of the Admiral Grigorovich frigates as Kyiv stopped supplying Russian defense contractors with the gas turbines necessary to power them (see EDM, January 25, 2017; The Moscow Times, June 8, 2015). Presently, only three ships have been commissioned.

Nevertheless, all six of the Kilo-class submarines have been delivered and commissioned. Furthermore, four of these submarines have fired their cruise missiles in anger in support of the Russian intervention in Syria (the Rostov-na-Donu, Krasnodar, Veliky Novgorod and Kolpino). In operational terms, this means that their crews are battle-tested and have a high degree of confidence in their boats and weapons systems.

A veteran of the Cold War, the Kilo diesel-electric attack submarine remains a potent weapons system to this day. It is one of the quietest conventional submarines in service and one of the safest. In the confines of the Black Sea and of the Eastern Mediterranean, these submarines can strike targets with torpedoes and cruise missiles with relative ease, while being protected by Russia’s burgeoning anti-access and area denial (A2/AD) “bubbles” (ROEC, July 14, 2015). Their capability to launch Kalibr cruise missiles makes them extremely dangerous, being able to hit targets well inside the Black Sea region, as well as in Europe, Central Asia and the Middle East. As such, the Kilo submarine is an A2/AD asset as well as an offensive power projection platform, capable of hitting NATO facilities in Central and Eastern Europe or to threaten the Deveselu missile defense base in Romania (see EDM, February 16, 2017; September 19, 2017).

Among NATO members in the Black Sea, region only Turkey has fully developed anti-submarine warfare (ASW) capabilities and can meet the challenge posed by Russian undersea vessels. Furthermore, Turkey’s control over the Bosporus and Dardanelles Straits allows for easy monitoring of transiting Russian submarines. However, Ankara’s ASW capabilities are divided between the Black Sea and the Mediterranean Sea and its readiness is being put to the test by Russia’s assertiveness. Romania and Bulgaria, the other two NATO members in the region that possess navies, are struggling to offer up any kind of effective response.

For NATO, the writing is on the wall—it needs to increase its ASW capabilities fast in order to deter the Russian submarine threat. As part of the European Reassurance Initiative (ERI) US P-8 Poseidon aircraft have begun patrolling over the Black Sea in order to track these submarines and gather intelligence. Nevertheless, the presence of Russian fighter aircraft as well as sophisticated air defense systems in and around Crimea makes the P-8s vulnerable to interception and/or interference (România Liberă, September 9, 2017). Clearly, besides a stronger Alliance presence in the region, there needs to be an overall increase in regional ASW capabilities.

An obvious response to the Russian submarine threat in the Black Sea is increasing Romania’s and Bulgaria’s naval capabilities. Romanian and Bulgarian navies operate old ships equipped mostly with outdated Russian sensors and weapons systems. Both countries have not acquired military vessels since joining the North Atlantic Alliance, mostly due to economic reasons. Nevertheless, the Russian military buildup in Crimea has created a sense of urgency concerning naval capabilities for Bucharest and Sofia.

In 2017, Bulgaria announced plans to acquire two multi-role corvettes (Defense News, August 29, 2017), in effect reviving a program dating back to 2007 (Novinite, October 2007). Romania is also preparing to acquire multi-role corvettes, which it views as the single most effective type of surface combatant for littoral areas (MApN.ro, December 8, 2017). Bucharest is likely to purchase four such vessels in a program that will span seven years and is estimated to be worth $1.9 billion. Furthermore, the Romanian Navy plans to modernize its vintage Type 22 frigates, acquired from the United Kingdom in 2003, using the offset agreement from the corvette purchase (MApN.ro, December 8, 2017). A decision concerning the corvette program is expected in 2018. Plans have also been drawn up to buy submarines; but such an acquisition process may not begin until sometime between 2020 and 2026 (Agerpres, January 26, 2017).

Besides looking to obtain new ships for their aging fleets, Romania and Bulgaria have been involved, since 2014, in numerous US- and NATO-led naval exercises in the Black Sea and the Mediterranean. Exercises like Sea Breeze 2017 (C6f.navy.mil, July 25, 2017) have included not only a large number of NATO allies, but also Ukraine and Georgia, targets of Russian aggression. Increasing the number of NATO joint exercises in the Black Sea sends a clear deterrence signal to Moscow, while also increasing capabilities and readiness at a fraction of the cost of new military acquisitions.

In the short term, it seems that Russia has the upper hand in the Black Sea region due to its fast-paced rearmament drive and sophisticated A2/AD assets. However, NATO can overcome this threat by developing regional capabilities designed to thwart apparent Russian advantages. Smart defense investments in critical capabilities, such as ASW, combined with complex joint exercises can restore the regional military balance in favor of the Alliance.