China’s People’s Liberation Army Navy (PLAN) already has the world’s largest navy by the total number of active warships and submarines (battle force ships).
The US Department of Defense (now Department of War) states that China’s navy “is the largest navy in the world with a battle force of over 370 platforms [i.e., ships], including major surface combatants, submarines, ocean-going amphibious ships, mine warfare ships, aircraft carriers, and fleet auxiliaries”.
“The… overall battle force [of China’s navy] is expected to grow to 395 ships by 2025 and 435 ships by 2030. The U.S. Navy, by comparison, included 296 battle force ships as of September 30, 2024, and the Navy’s FY2025 budget submission projects that the Navy will include 294 battle force ships by the end of FY2030,” the US Congress research paper said.
However, the US still enjoys a technological and numerical advantage in terms of aircraft carriers and submarines.
The US Navy has 11 aircraft carriers, all of them nuclear-powered. In comparison, China currently has only three operational aircraft carriers, none of which is nuclear-powered.
China will not be able to narrow the US advantage in terms of aircraft carriers for many decades. However, in the critical domain of undersea warfare, Beijing might be closer than ever in bridging the gap with the US.
According to the Nuclear Threat Initiative (NTI), the US Navy currently has 71 submarines, all of them nuclear-powered.
This list includes 14 Ballistic Missile Submarines (SSBNs), 53 Nuclear-Powered attack submarines (SSNs), and four Guided Missile Submarines (SSGNs).
Similarly, according to the NTI, China has 60 submarines, of which only 12 are nuclear-powered.
China has six Ballistic Missile Submarines (SSBNs), six Nuclear-powered attack submarines (SSNs), and 48 Diesel-electric attack submarines (SSKs). Of the 48 SSKs, 12 submarines feature Air-independent propulsion (AIP), a technology that makes them quieter and allows them to stay submerged longer.
While China has not yet operationalized a nuclear-powered aircraft carrier, Beijing has nearly half a century of experience with nuclear-powered submarines, as China’s first nuclear-powered submarine entered service in 1974.
In recent years, China has made particular strides in nuclear-powered submarines, whose greater speed, range, and endurance give its Navy greater reach.
China’s new Type 095 nuclear-powered attack submarine has a self-sustaining capability of about 90 days. It can carry 24 torpedoes and 16 vertical launch units, and is equipped with YJ-18 anti-ship missiles, CJ-10 land-attack cruise missiles, and HQ-10 anti-aircraft missiles.
In the coming years, while the US Navy submarine strength is set to decline as many of its submarines are on the cusp of retirement, the PLAN’s submarine strength is set to increase and even overtake the US Navy.
A 2023 US Department of Defense (DoD) report anticipates that China will grow its submarine force to 80 units by 2035. Nearly 20 of these subs could be nuclear-powered.
However, despite these impressive strides, the Japanese submarines could give PLAN sleepless nights.
China Vs Japan In Submarine Force
Compared to China, Japan has a modest submarine force.
According to the Global Firepower Index 2025, Japan has 24 submarines, less than half the number of Chinese submarines (60).
Furthermore, none of the Japanese submarines is nuclear-powered. As noted above, China has a fleet of 12 nuclear-powered submarines.
However, despite the PLAN’s qualitative and quantitative edge, Japanese submarines could give it a tough time.
Firstly, more than one-third of Japanese submarines feature Air-independent propulsion (AIP), a technology that makes them quieter and allows them to stay submerged longer.
Ten of the Japanese Soryu class submarines, operational since 2009, feature Stirling AIP with traditional lead-acid batteries.
These Soryu-class diesel-electric submarines, also known as 16SS, use AIP technology based on Kockums Stirling engines, licensed-built by Kawasaki Heavy Industries, allowing them to stay submerged for extended periods (up to two weeks).
According to British author and researcher Jack Buckby, Japan’s Sōryū-class submarines are among the world’s most advanced conventional boats.
Built jointly by Mitsubishi Heavy Industries (MHI) and Kawasaki Heavy Industries (KHI), the class features a distinctive X-shaped stern that provides superior maneuverability in shallow waters.
It’s a feature that many modern submarine programs have since copied.
The Sōryū-class is among the largest conventional submarines to have ever been built, measuring around 84 meters long and 9.1 meters wide, while also displacing roughly 4,200 tonnes submerged.
Despite being non-nuclear, its size and range give it near-blue-water capability, enabling it to operate far from home waters for extended periods.
Featuring a distinctive X-shaped stern for stealth and maneuverability, advanced sonar, and a potent torpedo/missile armament, the Sōryū class is a key asset for Japan in countering regional threats like China and North Korea.
The final two boats of the Sōryū-class feature more advanced lithium-ion batteries, the first operational submarines of their kind in the world.
Lithium-ion batteries offer better endurance, higher power output, and reduced complexity.
Furthermore, Japan’s latest Taigei-class submarines (four operational so far) are also equipped with advanced lithium-ion batteries, eliminating the need for traditional AIP while achieving over 1 month submerged endurance in low-power mode.
Japan plans to build seven Taigei-class submarines. Last month, the Japan Maritime Self-Defense Force (JMSDF) launched its sixth Taigei-class submarine, Sogei, which is expected to enter service in March 2027.
Notably, so far, Japan is the only country known to have fitted lithium-ion batteries into SSKs, with South Korea expected to be the next country to do so with three 3,600-ton Jang Bogo-3 Batch 2 submarines. These vessels are scheduled to be commissioned from 2027.
Japanese submarines are also known to be quieter than many Chinese models, making them harder to detect for both potential hunters and targets.
Stephen Nagy, a professor of international relations at Tokyo’s International Christian University, said Japan’s operational submarines could definitely complicate the PLA Navy’s movements in key locations and threaten to be “a severe reputational headache”.
Fu Qianshao, a former member of the PLA Air Force, told the South China Morning Post (SCMP) that “Japan’s Self-Defence Forces still lag behind the PLA in most areas, but its submarines deserve Beijing’s attention and caution.”
Fu added that Japan’s submarine fleet “could pose a real threat to China. That’s why the PLA must strengthen its anti-submarine capabilities – both equipment and training.”
Additionally, there are many choke points near the Taiwan Strait and in the first island chain, such as the Miyako Strait, and Japanese submarines could threaten PLAN at these choke points.
Additionally, the Japan Maritime Self-Defense Force (JMSDF) has four helicopter carriers capable of launching F-35B fighter jets.
It also has advanced Aegis-equipped destroyers (e.g., Maya-class at 8,200 tons) boasting superior radar, missile defense, and vertical launch systems (VLS) cells for longer-range anti-ship strikes.
Recently, Japan signed a deal to acquire 400 Tomahawk cruise missiles from the US, which have a range of about 1,500km (932 miles).
Currently, the Japanese Kongo-class destroyer JS Chokai is in the US, where it is being modified to make it the first JMSDF ship capable of firing Tomahawk anti-ship missiles.
In September, Japan also became the first country to fire a ship-mounted hypersonic electromagnetic railgun at a target vessel at sea.
Tests achieved Mach 6 projectiles and over 200 rounds per barrel, advancing durability and velocity.
Electromagnetic railguns provide crucial advantages, such as unlimited magazine depth and cost competitiveness. Each hypersonic railgun shot could cost thousands of dollars, compared with millions for missiles.
When successfully integrated, the hypersonic electromagnetic railgun could disturb PLAN’s calculations in the East China Sea.
🇯🇵 Japan has successfully completed tests of its railgun aboard the ship Asuka, confirming the ability to accurately hit targets at significant distances.
During the firing trials from June to early July, projectiles reached speeds exceeding 2,500 m/s — far higher than… pic.twitter.com/7AHnNZ1MDW
— Visioner (@visionergeo) September 11, 2025
The technology enables Japan to sustain its maritime defense for weeks and months, without the financial burden of expensive missiles.
After 200 shots, a destroyer with a railgun could still have 80% capacity. This enables sustained fire, making it a powerful asset in combat.
While China’s navy is larger overall, the Japanese Navy’s focus on high-quality, technologically sophisticated capabilities and missile defense makes it a force to reckon with.
- Sumit Ahlawat has over a decade of experience in news media. He has worked with Press Trust of India, Times Now, Zee News, Economic Times, and Microsoft News. He holds a Master’s Degree in International Media and Modern History from the University of Sheffield, UK.
- He can be reached at ahlawat.sumit85 (at) gmail.com
