Beijing, February 18 China has significantly increased its production of nuclear-powered submarines over the past five years to the point where it is launching submarines faster than the US, threatening to negate a sea-power advantage that has long belonged to Washington, according to a report by a think-tank.
The buildup in the People's Liberation Army Navy's (PLAN) nuclear-powered submarine force includes both ballistic-missile and attack submarines, the International Institute for Strategic Studies (IISS) said.
During the years 2021 to 2025, China's submarine building surpassed that of the US in both numbers of submarines launched – 10 to 7 – and tonnage – 79,000 to 55,500, CNN said, quoting the IISS report.
China does not disclose fleet numbers.
This is a stark contrast to the 2016 to 2020 period, when China only added three submarines (23,000 tons) to the US Navy's seven (55,500 tons), according to the IISS analysis.
These numbers represent submarines launched but not necessarily completed and added to the active-duty fleet, where the US still maintains a significant advantage.
As of early 2025, China had 12 active nuclear-powered submarines, six ballistic-missile boats, and six guided-missile or attack boats, according to the IISS' "Military Balance 2025."
The US had 65 total submarines, with 14 of those being ballistic-missile boats.
China also maintains a large conventionally powered submarine fleet, with 46 boats, according to the "Military Balance."
The US has zero conventionally powered submarines, which – unlike nuclear-powered submarines – need to be refueled regularly.
To accommodate its nuclear-powered submarine fleet growth, Beijing has significantly expanded the Huludao yard of Bohai Shipbuilding Heavy Industry Co. in northern China, according to the report, headlined "Boomtime at Bohai."
This follows a US Congressional Research Service report last month, which said the US Navy is falling well behind its submarine-building goal of two Virginia-class attack boats per year, with US shipyards delivering only 1.1 to 1.2 submarines a year since 2022.
The US is also building new Columbia-class ballistic-missile submarines, but that program is at least a year behind schedule, with the first of the class, the USS District of Columbia, not expected to be delivered to the Navy until 2028, the admiral in charge of the program told Breaking Defence last week.
"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 observers say the Chinese navy is also building ships at a feverish pace, adding a ship a month and building almost a ship a month.
According to a recent BBC report, the Chinese navy has emerged as the world's largest, operating 234 warships compared to the US Navy's 219.
Between 2019 and 2023, China's four largest shipyards - Dalian, Guangzhou, Jiangnan, and Hudong-Zhonghua - produced 39 warships with a combined displacement of 550,000 tonnes, according to a study by the Centre for Strategic and International Studies (CSIS).
With the addition of Loudi, the Chinese navy has added 11 combat vessels, including the aircraft carrier 'Fujian' in 2025.
In addition to building its own fleet, China is supplying modern naval ships and submarines to its all-weather ally Pakistan.
Last December, China launched a fourth Hangor-class submarine named Ghazi to Pakistan.