The Underwater Sword of the Juche Country. Construction of a Nuclear Submarine
Continued. Start: The underwater sword of the Juche country
Kim Jong-un first announced the construction of a nuclear submarine in the DPRK in his speech on January 5, 2021, at the VIII Congress of the Workers' Party of Korea, and in March 2025, footage of Kim Jong-un visiting the submarine's construction site was released, showing fragments of its hull.
And so, on December 25, 2025, the Korean Central News Agency (KCNA) reported that the DPRK leader Kim Jong-un arrived to inspect the construction site of a nuclear submarine that will be armed with strategic missiles. rockets.
On this day, Comrade Kim Jong-un reviewed the progress of research on the new secret underwater weapon and outlined strategic plans for reorganizing the Navy and creating new units. Comrade Kim Jong-un, inspecting the nuclear submarine construction site, received a progress report...
The General Secretary of the Workers' Party of Korea and Chairman of State Affairs of the Democratic People's Republic of Korea, the respected Comrade Kim Jong-un, supervised the construction of an 8,7-ton nuclear submarine carrying strategic guided missiles on site...
The workforce, scientists, and technicians of the shipbuilding industry, who have risen to the glorious challenge of implementing our Party's course for the modernization of the Navy, are fully demonstrating their powerful self-reliance and boundless patriotic enthusiasm and are vigorously advancing the construction of a strategic nuclear attack submarine—one of the five main tasks for developing defense capability outlined at the 8th Party Congress...
Comrade Kim Jong-un noted that further strengthening the nuclear shield—our national prestige, our national image, the guarantee of the Republic's absolute security, and the reliable consolidation of its irreversible status—is the noble mission and duty of our generation. He emphasized the unwavering resolve of our Party and the Government of the Republic to ensure perpetual peace and absolute national security through the deployment of nuclear forces that enemies cannot help but fear.
Comrade Kim Jong-un said that we had persistently built a nuclear shield capable of reliably protecting national security and had the capacity to expand it as needed to ensure our national security. The new nuclear submarine, he continued, would be a significant and crucial change, allowing us and even our enemies to be confident in our war-deterrent capabilities.
Comrade Kim Jong Un noted that the Republic of Korea's plan to develop a nuclear submarine, recently agreed upon with Washington at Seoul's request, will lead to further instability on the Korean Peninsula, and that we consider this to be offensive behavior that seriously violates the security and maritime sovereignty of our state and a security threat that must be addressed.
The General Secretary of the Workers' Party of Korea and Chairman of State Affairs of the Democratic People's Republic of Korea, the respected Comrade Kim Jong-un, supervised the construction of an 8,7-ton nuclear submarine carrying strategic guided missiles on site...
The workforce, scientists, and technicians of the shipbuilding industry, who have risen to the glorious challenge of implementing our Party's course for the modernization of the Navy, are fully demonstrating their powerful self-reliance and boundless patriotic enthusiasm and are vigorously advancing the construction of a strategic nuclear attack submarine—one of the five main tasks for developing defense capability outlined at the 8th Party Congress...
Comrade Kim Jong-un noted that further strengthening the nuclear shield—our national prestige, our national image, the guarantee of the Republic's absolute security, and the reliable consolidation of its irreversible status—is the noble mission and duty of our generation. He emphasized the unwavering resolve of our Party and the Government of the Republic to ensure perpetual peace and absolute national security through the deployment of nuclear forces that enemies cannot help but fear.
Comrade Kim Jong-un said that we had persistently built a nuclear shield capable of reliably protecting national security and had the capacity to expand it as needed to ensure our national security. The new nuclear submarine, he continued, would be a significant and crucial change, allowing us and even our enemies to be confident in our war-deterrent capabilities.
Comrade Kim Jong Un noted that the Republic of Korea's plan to develop a nuclear submarine, recently agreed upon with Washington at Seoul's request, will lead to further instability on the Korean Peninsula, and that we consider this to be offensive behavior that seriously violates the security and maritime sovereignty of our state and a security threat that must be addressed.
This announcement was accompanied by photographs of the submarine under construction. Judging by them, its hull is almost completely formed, with even the installed retractable devices visible. This means that all the large equipment, including the nuclear power plant, has already been installed, and the ship can be expected to be launched soon.
Naturally, the new submarine's performance characteristics are highly classified, so they can only be judged by its appearance and contradictory, mostly dubious or simply fanciful, publications in foreign media. Such information was often obtained from satellite images, but alas, the submarine was now being built in a closed shed.
Nevertheless, it is noticeable that the hull has an optimal hydrodynamic shape, with the forward horizontal rudders mounted on the conning tower's enclosure to reduce interference with the sonar system. Six torpedo tubes, most likely 533 mm in caliber, are located in the bow, while the missile silos are located aft of the strong conning tower and partially within its enclosure, similar to their arrangement on the diesel-electric submarine "Kim Gun Ok young woong ho" (Hero Kim Gun Ok). It is possible that a similar set of ballistic and cruise missiles is also used. The submarine under construction is equipped with an advanced sonar system, as evidenced by the clearly visible side sonar antenna.
North Korean submarine
Kim Jong-un and his daughter oversee the construction of a nuclear submarine.
It's interesting to note that the submarine was built in a very tight timeframe, as such ships in Russia sometimes take decades to build. Several foreign sources are circulating rumors that Moscow had a hand in the project, or more precisely, its technical assistance, although this is unlikely.
North Korea's southern neighbor is also trying to keep up. Following the Asia-Pacific Economic Cooperation (APEC) summit held in October-November 2025 in Gyeongju, South Korea, US President Donald Trump announced that he would allow the Republic of Korea to build a nuclear-powered submarine. Later, visiting the US, National Security Advisor Wi Sung-lak noted that the parties had concluded that a separate agreement on nuclear submarines was necessary.
Trump proposed building the boats at a Philadelphia shipyard owned by South Korean company Hanwha Ocean, but South Korean President Lee Jae-myung is hoping they will be built in South Korea:
It is desirable that they be produced within the country, both from a military security and an economic point of view.
Furthermore, the presidents of the United States and South Korea agreed to an agreement that will allow the United States to supply low-enriched uranium fuel for submarines, a significant exemption from U.S. export control regulations. South Korea, in turn, will invest $150 billion in the U.S. shipbuilding sector, which will help South Korean companies confidently enter the American shipbuilding market.
As usual, the leaders of the North and South have made mutual accusations that plans to build nuclear submarines undermine security on the Korean Peninsula and around the world.
North Korea places a significant emphasis on small submarines in its naval doctrine. This allows for the rapid and cost-effective construction of a significant number of submarines, while also allowing for small submarines to operate in shallow coastal archipelagoes.
The DPRK uses such boats for reconnaissance, landing reconnaissance groups on the South Korean coast, and, if necessary, they can carry out torpedo strikes or lay minefields in coastal areas where larger-displacement boats cannot operate.
The construction of the first, still very primitive, minisubmarines likely began in North Korea as early as the early 60s. One of these two-man, unarmed boats, only 5,7 meters long, ran aground off the coast of South Korea in 1965, was abandoned by its crew, and fell into the hands of the South Koreans. It was clearly intended to deploy a reconnaissance or saboteur force behind enemy lines.
One of the DPRK's midget submarines, 1965
According to several publications citing CIA information, North Korea imported six 16-meter submarines from Yugoslavia in 1973-1974. This, in the author's opinion, is yet another propaganda hoax, as such submarines were not built in Yugoslavia and therefore were not exported. Unconfirmed reports have also surfaced regarding the construction of other types of "pocket" submarines in North Korea.
The next real step for North Korean shipbuilders was the so-called "Yugo" (approximately 26-29 units built since 1965) and "Yono" (36 built since 1965). In 1991, information emerged about the construction of larger "small" Sang-O-class submarines, and in 2011, the "Sang-O II," which also has a dubious Yugoslav connection, in this case considered a copy of the "Hero"-class submarines. However, this idea does not stand up to scrutiny, as the displacement of the "Hero" is almost five times greater than that of the "Sang-O," the number of torpedo tubes is three times greater, and so on. Nevertheless, it cannot be ruled out that Yugoslav specialists may have assisted in the design of North Korea's midget submarines.
Yono-class submarine
Yugo-class submarine. Interestingly, it has two propellers of different diameters.
Below are the approximate performance characteristics of ultra-small submarines. fleet DPRK, although this information in foreign sources is extremely contradictory and does not inspire much confidence.
⁎ Sang-O-class submarines were built in various variants: attack, armed with four (according to other sources, two) 533mm torpedo tubes; special-purpose (presumably two units were built), equipped with an airlock for combat swimmers and their carriers; in addition, these submarines can carry up to 16 naval mines on an external sling.
Sang-O II
An interesting development by North Korean engineers is the Taedong B—a fusion of a high-speed boat with additional torpedo armament and a midget submarine. The primary purpose of this boat-submarine is to deploy reconnaissance and sabotage teams behind enemy lines. Besides North Korea, these boats are also in service with Vietnam and the Iranian Islamic Revolutionary Guard Corps under the name Zulficar. Two Korean Taedong Bs were delivered to Iran in 2002, and Iran subsequently produced them independently.
The displacement is approximately 22 tons, with main dimensions of 17 x 3,3 x 3,5 meters. Separate propulsion systems are used for propulsion: when surfaced, two diesel engines drive their own propellers and two rudders, while when submerged, two electric motors drive other propellers in the nozzles and the rudders. Surface speed is 40 knots, while submerged speed is 3 knots. A snorkel is used to operate the diesel engine underwater at depths of up to three meters. The diving depth is at least 20 meters. The boat is armed with two 324-mm torpedo tubes for self-defense, a radar, an echo sounder, and a video camera, and can carry up to eight people, including a special task force.
Mini-submarine "Taedong B" - "Zulficar"
North Korea's small submarines have been involved in a number of incidents. We will only touch on the most notorious ones.
On September 17, 1996, a Sang-O-class submarine ran aground off the South Korean coast due to engine failure (the so-called Gangneung Incident), near the city of Gangnung, 100 miles from Seoul. According to the South Koreans, the submarine was supposed to evacuate previously abandoned agents. There were 26 people on board—the crew, the head of the Naval Foreign Intelligence Department, and two intelligence officers. After destroying the classified equipment, they disembarked and attempted to enter North Korean territory. On the night of September 18, the submarine was discovered by a local taxi driver, who reported it to the police.
A large-scale manhunt began, lasting until November 5, involving 43 soldiers and police officers, and a curfew was imposed in large areas of South Korea. On September 23, North Korean authorities demanded the return of the South Korean side. "a submarine that suffered an accident during a training mission", its crew members, and the bodies of the dead. Only one member of the Sang-O expedition managed to escape home; another was captured, and the rest died in the fighting. There were also losses among the pursuers. The captured submarine is currently on display in the South as a museum exhibit. In December, Pyongyang apologized to its southern neighbor for the incident, and in response, the South handed over the cremated remains of the dead.
South Koreans at the crashed Sang-O (the "Gangneung Incident")
Sang-O is a museum exhibit in South Korea.
Sang-O retractable devices
Inside a Sang-O type boat
In late June 1998, a Yugo-class submarine, entangled in fishing nets, was discovered off the coast of South Korea. Its crew was dead, likely suicides.
On March 26, 2010, near Baengnyeong Island in the Yellow Sea, the South Korean Navy corvette PCC 783 Cheonan, with a displacement of 1200 tons, exploded, broke into two parts, and sank. Of the 104 crew members, 46 died.
South Korean Navy corvette PCC-783 Cheonan
It should be noted that Baengnyeongdo and four other adjacent islands have been the subject of a territorial dispute between the two Koreas since 1953. South Korea unilaterally established a demarcation line north of these islands, claiming it as its territory, a move that was not recognized by the DPRK. In 1999, North Korea imposed the so-called maritime demarcation line, and in 2009 declared the waters disputed "kill zone" and called on Seoul "refrain from provocations in these waters".
South Korean authorities blamed Pyongyang for the corvette's sinking. An international investigative commission (US, UK, Australia, Sweden) reached the same conclusion, believing (and who would have doubted it!) that the ship was hit by a torpedo fired by a North Korean submarine, presumably a Yono-class submarine. According to South Korean experts, the torpedo exploded 6-8 meters below the ship's bottom, and the resulting hydraulic shock broke the corvette in half.
The North Korean government rejected this accusation, arguing that submarine operations, much less a torpedo attack, were impossible in this shallow area and demanded a joint investigation. Several independent experts, including South Korean and Russian, believed the corvette was destroyed by an internal explosion or by the detonation of an old naval mine.
As evidence, South Korea cited the aft section of a torpedo, containing propellers, an engine, and a steering gear, allegedly found near the Cheonan's sinking on May 15. Seoul claimed that these parts fully matched the schematic drawing of a North Korean-made CHT-02D torpedo (533 mm caliber, 7,35 m long, 1,7 tons, 250 kg warhead, passive acoustic and wake-guidance systems) published in a North Korean Voenexport brochure. A serial number in Korean script was also included. However, although these torpedo parts had only been on the seabed for about six weeks, they were heavily corroded, raising doubts about their origin.
A comparison of the drawing of a CHT-02D torpedo and parts of a torpedo found by the South Koreans (from a letter from the South Korean government to the UN Security Council)
However, the sinking of the Cheonan sharply exacerbated inter-Korean relations and led to a series of international sanctions against the People's Republic of Korea.
On July 7, 2023, at a military parade in Pyongyang to mark the 70th anniversary of the end of the Korean People's Fatherland Liberation War, the Haeil-2 nuclear-armed underwater drone, a kind of analogue of the Russian Poseidon, was demonstrated for the first time. According to the Korean Central News Agency (KCNA), work on creating such drones, named "Haeil" (Tsunami) nuclear-powered unmanned underwater attack ship, have been underway since 2012. More than 50 tests were conducted between 2021 and 2023. These drones are likely a further development of previously tested ones, such as the Haeil-1.
North Korea's Haeil-class underwater drones
On March 23, 2023, during one such test, a drone was detonated in Hongwon Bay between the cities of Hamhung and Sinpo off the east coast of North Korea, where a target was placed in the form of a simulated enemy port. The test was personally supervised by North Korean leader Kim Jong-un.
The mission of the nuclear strategic submarine weapons is to stealthily penetrate operational waters and create a super-scale radioactive tsunami by underwater explosion to destroy enemy naval strike groups and major operational ports,
- says the KCNA message.
The tests correctly assessed all the tactical and technical characteristics and navigational and technical indicators of the underwater nuclear strike drone, confirmed its reliability and safety, and fully confirmed its lethality.
Thus, the North Korean Tsunami drone could pose a danger primarily to US military bases in Guam and Hawaii, as well as to American bases and cities on the Pacific coast. Furthermore, this submarine Drone It can also be used against naval formations, primarily aircraft carriers, for which purpose, according to a number of experts, it is equipped with an acoustic homing system.
The Haeil-2 appears to be a mega-torpedo, approximately 16 meters long and 1,5 meters in diameter, with a pump-jet propulsion system and cruciform stern rudders. The technical specifications of this "wonder weapon" are highly classified, and information from South Korean and Western sources should be taken with a grain of salt.
The drone can be armed with either a conventional or a nuclear warhead. Expert opinions on the type of propulsion system are conflicting – some believe it will be diesel-electric, while others believe it will be nuclear powered by a compact nuclear reactor.
The latest tests were a response of sorts to US-South Korean military exercises held off the coast of the Korean Peninsula.
From all of the above, it should be clear that the DPRK's military doctrine is purely defensive. The harsh lessons of the Great Patriotic War of 1950-1953, when the American-South Korean aggressors killed up to 2 million civilians and destroyed virtually all cities and industrial plants, made North Korea one of the most heavily bombed countries in history. storiesTo avoid a repeat of this tragedy, North Korea is trying to keep its powder dry. Recall the threats of former and now-reigning US President Trump to strike North Korea, which he wisely rejected.
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