China is building submarines faster than ever, think tank says. Why that’s a problem for Washington

 China has ramped up its production of nuclear-powered submarines over the past five years to the point where it is launching subs faster than the United States, threatening to negate a sea-power advantage that has long belonged to Washington, a new think tank report says.

The buildup in the People’s Liberation Army Navy’s nuclear-powered sub force includes both ballistic-missile and attack subs, the report from the International Institute for Strategic Studies (IISS) says.

During the years 2021 to 2025, China’s submarine building surpassed that of the US in both numbers of subs launched – 10 to 7 – and tonnage – 79,000 to 55,500, says the report, which looked at shipyard satellite imagery to draw estimates of China’s construction.

Beijing does not disclose fleet numbers.

It’s a stark turnaround from the 2016 to 2020 period, when China only added three subs (23,000 tons) to the US Navy’s seven (55,500 tons), according to the IISS analysis.

The numbers represent subs launched but not necessarily completed and added to the active-duty fleet, where the US still maintains a large 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 subs, with 14 of those being ballistic-missile boats.

China also maintains a large conventionally powered sub fleet, with 46 boats, according to the “Military Balance.”

The US has zero conventionally powered subs which – unlike nuclear-powered subs – need to refuel regularly.

To accommodate its nuclear-powered sub 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.”

It comes after a Congressional Research Service report to Congress last month 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 subs 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 first-in-the-class USS District of Columbia not expected to be delivered to the Navy until 2028, the admiral in charge of the program told Breaking Defense 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 says.

The IISS report highlights two Type 094 ballistic-missile subs (SSBNs) that have been launched at the Huludao shipyard. With the ability to fire nuclear-armed ballistic missiles, the Type 094s add to Beijing’s growing nuclear triad of land-based intercontinental ballistic missiles and bombers, it says.

China is building submarines faster than ever, think tank says. Why that’s a problem for Washington | CNN