MELBOURNE, Australia — China is expanding its submarine base on the edge of the South China Sea, with satellite photos showing it’s building two new piers.

The imagery of the Yulin naval base on the southern tip of China’s Hainan Island taken by Maxar Technologies on July 31 and published on Google Earth show the structure for two new piers under construction, adding to the four existing piers at the site.

The new piers are being built to the north and south of the existing piers, connected to what appears to be newly reclaimed land. A dredger is seen on the satellite imagery adjacent to the new northern pier.

This measures 573 feet long and 67 feet wide, according to Google Earth’s measuring tool, while the southern pier measures 780 feet long and is of a similar width to its northern counterpart.

Neither the reclaimed land nor pier structures were seen in previous satellite images of the base; the next most recent in Google Earth was an image taken in February 2022.

The base is part of a large naval complex housing the South Sea Fleet of China’s People’s Liberation Army Navy, which is equipped with nuclear-powered attack and ballistic missile submarines. These includes six Type 094, or Jin-class, nuclear-powered ballistic missile subs, three of which are seen berthed on Maxar’s image of the base. A smaller submarine, measuring 107 meters (351 feet), which means it could be a Type 093, or Shang-class, nuclear-powered attack sub, is also be seen on an adjacent pier in the image.

Yulin also has a submarine cavern tunneled into the side of a mountain.

In addition to the submarine piers under construction, the base has seen the assembly of a pier for large surface ships, including China’s aircraft carriers. This has allowed the PLAN to homeport China’s second carrier, the Shandong, at Yulin.

A new dry dock to accommodate an aircraft carrier and a surface combatant is also being built, while a helicopter base at the nearby city of Sanya has also received a refurbishment with new hangars, an expanded parking apron and resurfaced runways.

The South Sea Fleet is also where most of the PLAN’s rapidly growing amphibious assault fleet, including the first Type 075 helicopter carrier and most of its Type 071 landing platform docks, are assigned. These ships, which are designed to transport troops via landing craft or helicopters, would be a vital component of any Chinese invasion of Taiwan, which Beijing considers a rogue province and has threatened to take back by force, if necessary.