North Korea tests two submarine-launched missiles, state media reports

North Korea tested two types of strategic cruise missiles launched from a submarine. The trials took place at sea off the country’s east coast. They mattered because they demonstrated a way to deliver missiles from a mobile platform rather than only from land. That can support North Korea’s broader effort to strengthen its war deterrent.

KCNA said the test-fire examined the reliability of North Korea’s war deterrents. It also aimed to improve the navy’s skill in carrying out strategic missions. One missile was identified as the Pulhwasal-3-31. North Korea had said it tested that same cruise-missile type from land the previous week.

Senior military officers watched the sea tests. KCNA said they caused no adverse impact on neighbouring countries’ security. The trials came during a wider burst of North Korean missile activity, including ballistic-missile launches and an October 3 hypersonic missile test.

A submarine-launched strategic cruise missile is a guided missile carried and fired by a submarine. “Strategic” means it is intended to support major national military objectives, such as deterring an opponent. A cruise missile usually travels through the atmosphere toward its target and can adjust its route during flight. Launching it from a submarine adds a concealed sea-based option.

A ballistic missile differs mainly in its flight path. It is propelled strongly during launch, then follows a high, arcing trajectory for much of its journey before descending toward its target. A cruise missile instead uses ongoing propulsion and guidance while flying more like an unmanned aircraft. The article identifies North Korea’s Pulhwasal-3-31 as a strategic cruise missile.

The article does not provide technical details about the missile’s range, speed, or warhead. It does show North Korea testing the same missile family from both a submarine and land, suggesting multiple launch options.

North Korea tested two types of submarine-launched strategic cruise missiles. The article names one of them as the Pulhwasal-3-31, which North Korea had also said it launched from land the previous week. The report does not name the second missile type. Thus, the test involved two missiles or missile types, but only one is specifically identified.

The launch was part of a larger sequence of weapons tests. Earlier in the same week, North Korea fired multiple ballistic missiles toward the sea off its east coast. On October 3, it tested a hypersonic intermediate-range missile designed to evade missile defences in South Korea and Japan. These launches followed other recent military activity.

The wider pattern shows repeated testing across different missile categories and launch methods. South Korea also tested a hypersonic weapon last week. The article presents this activity as part of worsening tensions between Seoul and Pyongyang, rather than as an isolated submarine trial.

Submarine launches can strengthen deterrence because the platform may be difficult to find. A land-based launcher is tied to a known area, even if it moves or hides. A submarine can operate underwater and change position across a large sea area. This creates uncertainty about where a missile might be launched and complicates an opponent’s planning.

The key mechanism is survivability. If an opponent cannot reliably locate and attack the submarine before launch, the submarine may remain available after a first strike. It can then provide a possible retaliatory option. That uncertainty can discourage an attack because the attacker cannot be sure it would eliminate every threat.

The article says North Korea tested missiles at sea and is developing a modern missile submarine. It does not say how difficult these particular submarines are to detect or whether they can retaliate after an attack. Those are general strategic reasons submarine-based systems can support deterrence.

North Korea’s modern missile-submarine program is incomplete. The article says the country is not yet believed to have launched a modern missile submarine in full operation. That gap matters because the recent test demonstrated submarine-launched missiles, but not necessarily a mature submarine fleet capable of regular strategic patrols.

Kim Jong Un has overseen the development of strategic ballistic and cruise missiles and has made a fully operational missile submarine a top military priority. Last year, he visited a submarine production facility. State media images showed an 8,700-tonne nuclear-powered missile submarine under construction. The article does not confirm that this vessel has entered service.

A working submarine could support a more survivable deterrent by giving North Korea another launch platform at sea. It could complicate an opponent’s efforts to locate and destroy its strategic forces. The immediate reality remains development and testing, not a confirmed fully operational modern missile submarine.

Security tensions have risen as North Korea and South Korea have tested increasingly advanced weapons. North Korea launched submarine-based cruise missiles, multiple ballistic missiles, and a hypersonic intermediate-range missile. South Korea also tested its first hypersonic missile under President Lee Jae Myung. These actions display military capability while increasing concern about escalation.

The tests have also become linked to direct competition. A South Korean military spokesperson described North Korea’s ballistic launch as a show of force after South Korea tested its own hypersonic weapon. Separately, a landmine blast in September wounded three soldiers in the Demilitarized Zone. Seoul blamed North Korea, and a joint investigation concluded North Korean forces planted the mines.

Seoul demanded an official apology, while Pyongyang accelerated military fortification along the DMZ. Inter-Korean relations have further soured under North Korea’s “hostile-states” policy. Diplomatic efforts remain stalled since denuclearisation talks collapsed in 2019, and no new Trump-Kim meeting has materialised.

Military deterrence is the effort to prevent an attack by convincing an opponent that aggression would bring unacceptable costs. It does not require fighting to succeed. The basic message is that an attack would trigger a response strong enough to outweigh any expected gain. North Korea’s state media described the submarine tests as examining the reliability of its war deterrents.

Two ideas are central: retaliation and survivability. Retaliation means a country can respond after being attacked. Survivability means enough forces remain usable despite an opponent’s first strike. Submarines can support survivability because they may be concealed and mobile. If an attacker cannot find and destroy them all, the threat of retaliation remains.

Deterrence is never automatic. It depends on whether an opponent believes the capability exists and whether leaders would use it. The article reports testing and submarine construction, but it does not establish the strength or reliability of North Korea’s complete deterrent. It does show that deterrence is a stated purpose of its military development.