China now building nuclear submarines faster than US - is Washington losing its undersea edge?

China has sharply accelerated the production of its nuclear-powered submarines over the past five years, outpacing the United States in new launches and narrowing a long-standing maritime advantage held by Washington, according to a report by a leading defence think tank.The expansion of the People’s Liberation Army Navy’s nuclear submarine fleet includes both ballistic-missile and attack submarines, the International Institute for Strategic Studies said in its latest assessment. Between 2021 and 2025, China launched more submarines than the US, commissioning 10 vessels compared with America’s seven. In terms of tonnage, China also led with 79,000 tonnes against the US total of 55,500 tonnes, CNN reported, citing the IISS study.Beijing does not officially publish detailed figures about the size of its fleet.The development marks a notable shift from the 2016 to 2020 period, when China added just three submarines with a combined displacement of 23,000 tonnes, while the US brought seven new submarines into service totalling 55,500 tonnes, according to IISS data.The figures reflect vessels launched rather than fully completed and deployed. Despite China’s recent surge, the US retains a significant overall advantage in operational nuclear submarines.As of early 2025, China was operating 12 nuclear-powered submarines, comprising six ballistic-missile boats and six guided-missile or attack submarines, according to the IISS publication Military Balance 2025.By contrast, the US Navy had 65 submarines in total, including 14 ballistic-missile boats.China also fields a sizeable fleet of conventionally powered submarines, numbering 46 vessels. The US operates no conventional submarines, relying exclusively on nuclear propulsion.To support its growing nuclear submarine programme, Beijing has expanded the Huludao shipyard operated by Bohai Shipbuilding Heavy Industry Co in northern China. The IISS report, titled “Boomtime at Bohai,” highlights the rapid pace of construction at the facility.The report comes as concerns mount in Washington over production delays. A recent US Congressional Research Service study noted that the US Navy is falling short of its target to build two Virginia-class attack submarines annually. Since 2022, American shipyards have delivered between 1.1 and 1.2 submarines per year.The US is also developing the Columbia-class ballistic-missile submarines. However, the programme is running at least a year behind schedule. The first vessel in the class, USS District of Columbia, is not expected to be delivered until 2028, according to remarks made to Breaking Defence by the admiral overseeing the project."The greater numbers in the water present a growing challenge to (the US and other Western) countries as they struggle to increase their own output," the IISS report said.Military analysts note that China’s naval expansion extends beyond submarines. A recent BBC report stated that China now operates 234 warships, compared with 219 in the US Navy, making it the largest navy in the world by vessel count.Between 2019 and 2023, China’s four major shipyards in Dalian, Guangzhou, Jiangnan and Hudong-Zhonghua built 39 warships with a combined displacement of 550,000 tonnes, according to research by the Centre for Strategic and International Studies.In 2025 alone, the Chinese navy added 11 combat vessels, including the aircraft carrier Fujian.China is also strengthening defence ties with Pakistan by supplying advanced naval platforms. In December last year, Beijing launched the fourth Hangor-class submarine, named Ghazi, for the Pakistani Navy.