How Submarine Power of U.S., Allies and Rivals Compare

The decision by the United States and Britain to join hands in helping Australia deliver its first nuclear-powered submarine fleet has highlighted the urgency of America and its allies to respond to China's growing maritime presence in the Indo-Pacific.

As a member of the Quad with the U.S., India and Japan, Australia is considered a key fixture in the region's collective security architecture. The newly formed AUKUS defense pact with the U.S. and U.K. will help Canberra establish a future fleet of eight submarines powered by nuclear reactors, replacing its six Collins-class diesel boats.

As an ANZUS alliance member with the U.S. and neighboring New Zealand, Australia doesn't need to compete with the People's Liberation Army (PLA) Navy in terms of size. U.S. officials have made clear how Australia's interoperable forces can help augment the U.S. Navy, which still operates the world's best-equipped and deadliest submarines.

The U.S. fleet of 68 active service subsurface vessels is fully nuclear-powered and includes 19 of its latest Virginia-class fast attack submarines. NATO allies France and U.K. operate 10 and six nuclear-powered submarines.

In Asia, the Japan Maritime Self-Defense Force commissioned its 21st submarine this year, while fellow U.S. treaty ally South Korea operates 18. Both navies run diesel-electric boats.

Russia, which was among the earliest powers to operate a nuclear subsurface ships during the Soviet Union, currently has 58 such vessels, including 37 with nuclear propulsion.

Surprisingly, it is another American Cold War foe, North Korea, that operates the world's largest submarine fleet in terms of sheer numbers—72 diesel-powered boats that are aging but still formidable.

The PLA Navy, however, remains the focus of much U.S. military realignment this decade and some say even in the coming century. According to 2020 Pentagon report, China's fleet of 60 submarines includes at least 10 nuclear-powered warships—its Jin-class boats forming its developing sea-based nuclear deterrent.

The Defense Department estimates China will operate a fleet of up to 70 submarines throughout this decade of rapid modernization, which has seen the country build 12 submarines in the last 15 years.

A recognition of this naval advancement partly explains Australia's decision to abruptly end a $65 billion contract with French shipbuilder Naval Group, which was to deliver a fleet of diesel-electric submarines.

Announcing the U.S.-led AUKUS partnership to help build up Australia's submarine fleet, Biden administration officials noted the superior stealth, speed, maneuverability, survivability and endurance of nuclear-powered variants. Diesel boats are smaller and can operate in the shallows, but they require regular surfacing and the charging of batteries.

Officials involved in AUKUS will spend their first 18 months drawing up plans for Australia's new submarine program. It is expected to include a determination of whether the new boats will be American Virginia-class or British Astute-class submarines.

China's PLA Navy Parades New Conventional  Submarine
File: A Chinese People's Liberation Army Navy submarine participates in a naval parade to commemorate the 70th anniversary of the founding of China's navy near Qingdao, Shandong, on April 23, 2019. - China celebrated the 70th anniversary of its navy by showing off its growing fleet in a sea parade featuring a brand new guided-missile destroyer. (Photo by Mark Schiefelbein / POOL / AFP) (Photo credit should read /) MARK SCHIEFELBEIN/AFP via Getty Images