The Buyan-M class (Russian: Буян-М, lit. 'Buyan-M'), Russian designation Project 21631 Buyan-M are a series of corvettes (small missile ships by Russian classification), in service with the Russian Navy. They are an updated version of the earlier Project 21630 Buyan-class corvettes. The ships are primarily designed for operations within littoral zones to protect Russia's vast coastal areas. Due to their small tonnage, they can operate even within shallow parts of oceans and seas and Russia's inland waterway system. The lead ship of this project, Grad Sviyazhsk, was laid down on 27 August 2010 and commissioned on 27 July 2014.
Characteristics
=== Structure === The Project 21631 ships are significantly larger than their predecessor, with a displacement of 949 tonnes (934 long tons) compared to 508 tons, and a length of approximately 75 m (246 ft) rather than 62 m (203 ft). Due to their small tonnage, Buyan-M-class corvettes can operate in Russia's inland waterways. The interconnected rivers and canals of Russia's inland waterway system provide routes between the Caspian, Baltic, White and Black seas.
=== Propulsion === The first five ships of this class each use 4 German MTU 16V4000M90 diesel engines and ZF gearboxes. However, after the beginning of the Russo-Ukrainian war, MTU engines became unavailable due to sanctions imposed on Russia. Russian officials had stated that "a replacement for the sanctioned engines had already been found, and production of ships would not pause." 4 CHD622V20 diesel engines were used instead on the next four ships. These engines were produced by the Chinese company HND and feature a common rail system and a turbocharger. Later, as part of Russia's drive to replace imported goods with domestic ones, and also because of alleged unreliability of Chinese engines, the final three ships of the class received Russian-made 16D49 diesel engines. The engines were made by Kolomna Locomotive Works, use a gearbox made by Zvezda, and NPO Avrora control systems.
=== Armament === The Buyan-M class differs greatly in armament from its preceding variant. Original Buyan ships are fitted with an A-215 Grad multiple rocket launcher. The Buyan-M units, however, are equipped with an 8-cell 3S-14 vertical launching system, which is intended to carry the nuclear-capable Kalibr long-range cruise missile, and the supersonic Oniks cruise missile. The Buyan-M corvette also carries two Gibka surface-to-air missile systems, each equipped with 4-8 Igla MANPADS, although images normally show four or six missiles installed. Another weapon system on the Buyan-M class is the AK-630M2 "Duet" which consists of two AO-18 rotary cannons one above the other. It was rumored that the final ship of the class, Stavropol, would be fitted with a Pantsir-M system as on Karakurt-class corvettes, but this did not become reality. Before its collapse in 2019, the Intermediate-Range Nuclear Forces Treaty prohibited ground-launched ballistic and cruise missiles with ranges of 500–5,500 km, but did not restrict sea-launched missiles. The deployment of Kalibr land-attack cruise missiles aboard river-capable Buyan-M corvettes therefore provided Russia with a long-range strike capability not subject to these restrictions.
History
=== Design === The Buyan-M project was developed by the Zelenodolsk Design Bureau for the Russian Navy and built by the JSC Zelenodolsk Shipyard in Tatarstan. It is an updated missile-carrying variant of the earlier Buyan-class artillery ships, with a greater displacement, different armament, and upgraded electronics. Buyan-M ships are designed to operate in shallow waters like rivers, lakes, deltas, and some parts of seas and oceans. These corvettes are intended for protection of Russia's national economic zone.
=== Construction and deployment === Allegedly, a ship of the Buyan-M-class was intended to be built at the Almaz Shipbuilding Company in Saint Petersburg. The construction was cancelled, and little further information is available.
Initially, 8–10 ships of the class were planned, to serve with the Caspian Flotilla and the Black Sea Fleet, and later reporting established that there would be 9 ships of the class, 3 for the Caspian Flotilla and 6 for the Black Sea Fleet. Ultimately, 12 ships of the class were built, with the final three serving with the Baltic Fleet, along with two being transferred from the Black Sea Fleet to the Baltic Fleet. On 28 March 2022, a Buyan-M class corvette fired eight Kalibr missiles from the Black Sea and destroyed a Ukrainian arsenal at Orzhev, according to Russian reporting.
By ship
Grad Sviyazhsk
Uglich
Velikiy Ustug
===== Zeleny Dol ===== In 2016 Zeleny Dol was deployed to the Mediterranean Sea, later followed by sister ship Serpukhov. On 19 August Zeleny Dol and Serpukhov, deployed in the Mediterranean Sea, launched Kalibr cruise missiles at positions of Al-Nusra terrorist group in Syria. As a result of the strikes, number of terrorist facilities were destroyed, including command post and base near the village of Dar Ta Izzah and weapon production plants and warehouses in Aleppo province. On 25 October 2016, Zeleny Dol and Serpukhov were deployed to the Baltic Sea to join a newly formed division at Kaliningrad. In 2020, Zeleny Dol and the Karakurt-class corvette Odintsovo deployed to Arctic waters utilizing Russian internal waterways.
Serpukhov
===== Vyshniy Volochyok ===== Published Russian naval documents showed that on 7 August 2025 the Vyshniy Volochyok was damaged from colliding with the civilian tanker Nazan in Temryuk Bay while maneuvering to evade attacking Ukrainian drones.
===== Ingushetiya ===== On 13 November 2019, the Ingushetiya performed a test-launch of a dummy Kalibr missile while on its factory sea trials in the Black Sea. The Ingushetiya also tested its artillery systems against maritime and coastal targets.
===== Grad ===== On October 4, 2025, the Ukrainian Special Forces reported that the Grad was damaged after being struck by Ukraine, on Lake Onega.
== Ships == Hull numbers and yard numbers from Russianships.info.