North Korea Expands Submarine and Hypersonic Missile Programs

North Korea test-fired two types of submarine-launched strategic cruise missiles off its east coast, according to state media KCNA. The Wednesday tests were intended to assess the reliability of the country’s deterrence capabilities and improve the navy’s ability to carry out strategic missions. One of the missiles was a Pulhwasal-3-31, a type North Korea said it had also launched from land the previous week. Senior military officers observed the tests, and KCNA claimed they posed no risk to neighbouring countries. North Korea is not believed to have a modern missile submarine in full operation, although developing one is a key military priority for leader Kim Jong Un. During a visit to a submarine production facility last year, Kim criticised a nuclear submarine deal between the United States and South Korea. State media images from the visit showed an 8,700-tonne nuclear-powered missile submarine under construction; Kim described the US-South Korea deal as a threat to stability on the Korean Peninsula. The tests come amid a recent increase in North Korean missile activity and worsening relations between Pyongyang and Seoul. North Korea has launched multiple ballistic missiles toward the sea and, on October 3, tested a hypersonic intermediate-range missile designed to evade defences in South Korea and Japan. South Korea has also displayed its own hypersonic weapons programme, including a test overseen by President Lee Jae Myung. Tensions have also risen after a landmine blast in the Demilitarized Zone wounded three South Korean soldiers. A joint South Korean-United Nations investigation said North Korean forces planted the mines, prompting Seoul to demand an apology. The article links Pyongyang’s military fortification along the DMZ to Kim’s “hostile-states” policy, which aims to sever ties with South Korea. Diplomatic efforts remain stalled following the collapse of denuclearisation talks between Washington and Pyongyang in 2019. Although Donald Trump has suggested he might meet Kim during his second term, no meeting has taken place.

The article examines how hypersonic weapons are becoming the latest focus of the long-running arms race between North and South Korea. North Korea reported testing two types of submarine-launched cruise missiles and publicized Kim Jong Un’s visit to a defense industry museum displaying an intercontinental ballistic missile it says can reach the continental United States. These developments followed South Korea’s first test launch of a domestically developed hypersonic missile and North Korea’s earlier test of a missile it described as hypersonic, which it said traveled 350 kilometers before hitting its target. Hypersonic missiles can travel at least five times the speed of sound and maneuver in flight, making them harder to track and intercept. International Crisis Group analyst Chris Green describes their development as the latest expression of a broader arms race. He says South Korea sees the technology as a priority in response to North Korea’s expanding capabilities and its closer military and economic ties with Russia. North Korea, meanwhile, is pursuing advanced conventional weapons amid regional competition, despite the severe consequences it would face for using nuclear weapons. Experts caution that North Korea’s claims are difficult to verify, but say it would be imprudent to dismiss them. Retired South Korean General Chun In-bum notes that Pyongyang’s technological progress appears abrupt and speculates that it may have obtained information through illicit means. He warns that weapons that are more difficult to intercept could increase the danger and tempt their use, while acknowledging that there is currently no obvious solution to the threat. The article concludes that hypersonic systems are not, by themselves, a game changer in the balance of power. Green argues that each side’s capabilities may offset the other, and North Korea retains its nuclear deterrent. However, if the North deploys large numbers of increasingly capable offensive weapons, South Korea and Japan may need to consider stronger missile defenses, raising difficult strategic questions.

North Korea said it had test-fired cruise missiles intended for submarine launch, describing the tests as a way to check the readiness of its underwater combat systems and strengthen the Navy. State media said the missiles were tested in waters off the Korean Peninsula’s east coast. It called them “strategic,” a term that suggests they could be intended to carry nuclear warheads, but did not clarify whether the missiles were launched from an operational submarine or an underwater test platform. The test is part of North Korea’s broader development of missile submarines and ballistic and cruise missiles. Pyongyang has conducted a series of weapons tests in recent weeks, presenting them as efforts to strengthen its military deterrence against the United States and South Korea. The article notes that North Korea is not yet believed to have put a modern missile submarine into full operation. The report also describes recent developments in North Korea’s nuclear and diplomatic posture. Two days before the missile test, state media published photos of leader Kim Jong Un visiting a new military museum at an undisclosed location. The museum displayed an intercontinental ballistic missile reportedly capable of reaching the United States. Kim has identified expansion of the country’s nuclear arsenal as a key priority, while denuclearization—the goal pursued by the United States—is described as off the table. Relations between Kim and US President Donald Trump have been quiet since their three meetings during Trump’s first term. Trump recently suggested he might meet Kim during a planned trip to Asia. Meanwhile, North Korea has halted coordination with South Korea and removed references to reunification from its constitution.

North Korea test-fired two types of submarine-launched strategic cruise missiles on Wednesday, October 14, according to state news agency KCNA. The missiles were fired into the East Sea, also known as the Sea of Japan. KCNA said the tests had no adverse effect on neighboring countries and described them as a Navy training exercise intended to assess the readiness of underwater combat systems. The agency said the launches demonstrated the reliability and capability of North Korea’s deterrence forces. The tests took place amid increased tension with South Korea following a September 21 landmine explosion in the Seoul-controlled area of the Demilitarised Zone (DMZ), which injured three South Korean soldiers. Both countries have pursued upgraded missile technologies since the incident. KCNA-released photographs appeared to show missiles launching vertically and at an angle, as well as a missile flying over the sea and a submarine at the surface. Hong Min of the Korea Institute for National Unification told AFP that the two launch angles have different tactical uses: vertical launches may extend a missile’s range, while angled launches can keep it at lower altitude and make it harder for missile defences to detect or intercept. North Korea has conducted submarine missile launches in recent years, but the extent of its sea-based capabilities remains uncertain. Cruise missiles generally fly lower than ballistic missiles, which can make them harder to detect and intercept. A proven submarine-launched ballistic missile capability would represent a more consequential advance, potentially enabling deployment farther from the peninsula and a second-strike capability. The launches come amid multiple missile tests by both Koreas. North Korea conducted several ballistic missile tests in October, while South Korea and North Korea have also tested hypersonic weapons. The article notes that the two countries remain technically at war because the 1953 Korean conflict ended in a truce, not a peace treaty.

North Korea conducted its first publicly reported underwater-launched missile tests in nearly three years, firing two types of strategic cruise missiles in waters off its eastern coast. The tests, announced by the state-run Korean Central News Agency, were presented as a way to assess underwater combat readiness and demonstrate the reliability of the country’s nuclear deterrent. South Korea’s Joint Chiefs of Staff said it detected the launches and assessed that one missile was fired from a vertical launch tube and the other from a torpedo tube. Images released by North Korean media suggested the launches may have involved the Hero Kim Kun Ok, a submarine unveiled in 2023 that Pyongyang says can carry tactical nuclear weapons. Foreign experts have questioned whether the aging diesel-powered vessel can perform as claimed, and the absence of known weapons tests from it had raised suspicions of technical problems. Analysts say Wednesday’s activity may indicate those issues have been addressed and could precede further testing, including ballistic missile launches, before the submarine enters service. Its deployment could make North Korean weapons harder to detect and pose a significant threat to South Korea and the United States. The launches fit a broader expansion of North Korea’s weapons demonstrations and naval capabilities. Kim Jong Un has recently emphasized strengthening the navy, and North Korea unveiled a nuclear-powered submarine under construction in March 2025. The missile tests also followed hypersonic weapons demonstrations in September and October and came amid stalled diplomacy with Washington. Pyongyang has rejected a US effort to revive talks and has said it would consider diplomacy only if Washington drops its “hostile” policy and stops making denuclearization a precondition. Analysts interpret the submarine tests as an effort to build leverage and signal that North Korea intends to retain—and expand—the reach of its nuclear arsenal.