Yes, North Korea Has A Tactical Nuclear Submarine: Here's What We Know

The People's Democratic Republic of North Korea (DPRK), better known in the West as North Korea, entered the Atomic Age in October 2006. That's when it was revealed that the DPRK detonated its first atomic bomb. Since that first test, the nation has fast-tracked its nuclear development to improve on munitions, outfit them onto various types of rockets, and much more. The DPRK is a nuclear power, and it has a variety of means of delivering its weapons.

When people think of nuclear-capable countries, they may discount the DPRK, but that isn't something the nation's leader, Kim Jong-un, would appreciate. To his and the nation's pride, the DPRK has its very own tactical nuclear submarine, and if the reports are accurate, it's somewhat comparable to the United States' own Ohio-class nuclear submarines' ability to launch nuclear-armed missiles, though at a much shorter range. These vessels loiter in the world's oceans, ready to deploy radioactive doom anywhere on the planet.

Of course, the U.S. has been developing and improving its nuclear arsenal and submarine fleet for decades, so the DPRK has plenty of work to do to catch up. Still, the DPRK's use of a nuclear-armed submarine shouldn't be discounted. The weapons developed by the country are incredibly deadly, and if its new toy, the "Hero Kim Gun-ok," proves to be at least partially capable of maneuvering through the world's waters, it could theoretically pose a threat to Western nations.

The DPRK didn't build its new toy in-house, as its shipbuilding industry is somewhat lackluster. Instead, the nation typically buys warships from other nations and then alters them for its purposes. In the case of the Hero Kim Gun-Ok, the vessel started life as a Cold War-era, Soviet-built Romeo-class submarine. The Soviet Union operated Romeo-class subs under Project 633, which began in the early 1950s. Eventually, the USSR sold its submarines and their plans to other nations, including the DPRK.

The DPRK owns 20 Romeo-class submarines, but the Hero Kim Gun-Ok is different, as it's been modified into a tactical nuclear attack submarine. While it reportedly carries nuclear weapons, the submarine is likely powered by diesel engines. Thus far, it appears that the Hero Kim Gun-ok is the only such vessel in the DPRK inventory. When it was revealed to the world in September 2023, Kim Jong-un was on hand to proudly watch it enter the sea.

The vessel was heavily modified to potentially accommodate four ballistic missiles and six cruise missiles. These missiles are likely the most advanced in the DPRK arsenal and are considered to be reliable. While it's not confirmed, it's believed that the ballistic missiles are the KN-23 Hwasong-11S, which has a maximum range of 428 miles. They can carry warheads weighing up to 2.5 tons, though it's unclear what their nuclear yields would be.

While most of the technical details about the Hero Kim Gun-Ok aren't known outside of the DPRK, it's possible to surmise its capabilities based on the information that is available. As a Romeo-class submarine, the Hero Kim Gun-Ok submarine likely operates via diesel engines. It's relatively small, only stretching 282 feet in length. The Ohio-class submarines operated by the U.S. are 560 feet long, dwarfing the DPRK's latest piece of military hardware.

In addition to the nuclear-armed missiles the sub can launch, it's also believed that it will be able to deploy the Haeil, an unmanned nuclear-armed underwater drone, which the nation unveiled in March 2023. The sub is reported to displace around 1,830 tons of water and can reach speeds of just under 13 knots (15 mph), so it's not a fast vessel. It's also unclear as to whether the Hero Kim Gun-Ok is outfitted with torpedo tubes.

Reconfiguring it for submarine-launched ballistic missiles (SLBM) apparently sacrificed its standard armament. Romeo-class submarines aren't the best in the world by any measure, and it appears the DPRK sacrificed several elements to convert one into a tactical nuclear missile submarine. Analysts have indicated that the DPRK may have exaggerated the vessel's capabilities, which isn't unusual when talking about the isolated nation.

The Hero Kim Gun-Ok is vastly different from other missile submarines operated by the DPRK. Previously, Sinpo-C-class submarines, which are also modified Romeos, were believed to carry a smaller number of short-range ballistic missiles (SRBM). The addition of a new vessel capable of carrying far more missiles suggests the DPRK is modifying its submarine strategy to include a variety of launch-capable systems.

While few people outside the defense industry consider the DPRK's submarine fleet, it's actually quite large. It's believed that the nation operates as many as 86 submarines of different classes. These include around 40 Sang-O-class coastal submarines (SCC), 20 Romeo-class subs, two ballistic missile submarines (SSBNs), and another 21 Yugo and Yono-class mini-submarines. All are powered conventionally, including the newly-added Romeo-Mod-class that is the Hero Kim Gun-Ok.

For comparison, the U.S. operates 68 submarines as of August 2024. Granted, American submarines are larger, more technologically advanced, and largely incomparable to those operated by the DPRK. Despite this, the fact that the DPRK has so many active submarines is indicative of the nation's interest in expanding its military reach beyond its own borders.