The first version had the Soviet designation Project 877 Paltus (Russian: Па́лтус, meaning "halibut"), NATO reporting name Kilo.

[5] They entered operational service in 1980 and continued being built until the mid-1990s, when production switched to the more advanced Project 636 Varshavyanka variant, also known in the West as the Improved Kilo class.

Anechoic tiles are fitted on casings and fins to absorb the sound waves of active sonar, which results in a reduction and distortion of the return signal.

On 27 July 2012, the Russian Navy commander-in-chief announced that construction of the Lada-class submarines would resume, having undergone design changes.

[15][needs update] The Russian Navy also moved forward in the late 2010s, with the construction of Project 636.3, also known as Improved Kilo II.

The first-in-class was named Petropavlovsk-Kamchatsky (PPK) and was launched by the head of Admiralty Shipyard Alexander Buzakov on 28 March 2019, or some thirty months after commission.

[4] In June 2022, an unconfirmed report from within Russia's defense industry suggested that a further tranche of six additional Project 636.3 vessels might be ordered to start construction in around 2024.

[18] The Kilo-class submarine Yuanzheng 72, deployed on a combat readiness voyage encountered a "cliff" caused by a sudden change in seawater density.

Because the seawater density suddenly decreased, the submarine lost its buoyancy and rapidly fell to the seabed more than 3,000 metres (9,800 ft) deep.

At least two of the units reportedly attacked land targets inside Syria with 3M54 Kalibr cruise missiles (NATO designation: SS-N-27A "Sizzler").

[23] In September 2022, after the early 2022 Crimea attacks, the UK Ministry of Defence said that the Kilo-class submarines were moved from Sevastopol to the Port of Novorossiysk in Krasnodar Krai.

About forty vessels have been exported to several countries: The government of Venezuela expressed interest since 2005 in acquiring nine AIP-powered conventional submarines, either the German U214 or later the Amur 1650.