"The terms of the six submarines’ deliveries are: two in 2019, two in 2020 and two in 2021," Director General Alexander Buzakov told reporters at the Army-2016 military forum near Moscow.
Buzakov and Deputy Defense Minister Yuri Borisov signed a contract on the construction of the six advanced stealth technology submarines at the forum earlier in the day.
The shipyard, which is affiliated with the United Shipbuilding Corporation, launched the last of the six submarines for the Black Sea Fleet last May.
The Varshavyanka-class (Project 636.3) is an improved version of Kilo-class submarines that features advanced stealth technology, extended combat range and the ability to strike land, surface and underwater targets.
The vessels, carrying crews of 52, have a top underwater speed of 20 knots and a cruising range of 400 miles (electric propulsion), with the ability to patrol for 45 days. The submarines are armed with 18 torpedoes and eight surface-to-air missiles.
The submarines are mainly intended for anti-ship and anti-submarine missions in relatively shallow waters.