Kilo II-class Hunter-Killer Submarine

The Project 636 Varshavyanka-class submarine (NATO reporting name Kilo-II) is an improved version of the Kilo I-class submarine. Project 636 boats are equipped with improved MGK-400EM, with MG-519 Arfa also upgraded to MG-519EM. The improved sonar systems have reduced the number of operators needed by sharing the same console via automation. Algeria, the People's Republic of China, Russia and Vietnam all operate the Kilo II-class. Prospective users include Indonesia (two subs), the Philippines (three subs) and Venezuela (three subs).

Algerian National Navy

 * Messali el Hadj (021)
 * Akram Pacha (022)

People's Liberation Army Navy

 * PLANS Yuan Zheng 66 Hao (366)
 * PLANS Yuan Zheng 67 Hao (367)
 * PLANS Yuan Zheng 68 Hao (368)
 * PLANS Yuan Zheng 69 Hao (369)
 * PLANS Yuan Zheng 70 Hao (370)
 * PLANS Yuan Zheng 71 Hao (371)
 * PLANS Yuan Zheng 72 Hao (372)
 * PLANS Yuan Zheng 73 Hao (373)
 * PLANS Yuan Zheng 74 Hao (374)
 * PLANS Yuan Zheng 75 Hao (375)

Russian Navy

 * RFK Novorossiysk (B-261)
 * RFK Rostov-on-Don (B-237)
 * RFK Stary Oskol (B-262)
 * RFK Krasnodar (B-265)
 * RFK Veliky Novgorod (B-268)
 * RFK Kolpino (B-271)
 * RFK Petropavlovsk-Kamchatsky (B-274) - sea trials
 * RFK Volkhov (B-603) - under construction
 * RFK Magadan - under construction
 * RFK Ufa - under construction
 * RFK Mozhaysk - planned for construction
 * RFK Unnamed - planned for construction

Venezuelan Navy

 * ARV Picua (S-41) - planned for construction
 * ARV Tiburon (S-42) - planned for construction
 * ARV Carite (S-43) - planned for construction

Vietnam People's Navy

 * Hà Nội (HQ-182)
 * Hồ Chí Minh City (HQ-183)
 * Hải Phòng (HQ-184)
 * Khánh Hoà (HQ-185)
 * Đà Nẵng (HQ-186)
 * Bà Rịa-Vũng Tàu (HQ-187)