In May, the Philippines and China took turns installing buoys in the disputed Spratly Islands. The deployment of buoys and other sovereignty markers in the South China Sea has a long history. But amid a flurry of new activity by the Philippines, including publicized patrols and surveillance missions, it is noteworthy that the buoy deployment triggered an almost immediate reaction from China, which installed its own. And with the Philippines planning to install more buoys by the end of 2023, this trend will remain a point of contention between Manila and Beijing for the foreseeable future.
On May 15, the Philippine Coast Guard installed 30-foot navigational buoys at five features in the Spratly Islands: Philippine-occupied Flat Island, Loaita Island, and Loaita Cay, and unoccupied Irving Reef and Whitsun Reef. The buoys are of the same type as five installed in May of 2022 at four Philippine-occupied features: Nanshan Island, West York Island, Northeast Cay, and Thitu Island.
China responded by deploying its own “navigational beacons” to China-occupied Gaven Reef, as well as Whitsun Reef and Irving Reef, meaning those two unoccupied features now host both Chinese and Philippine buoys. While both sides touted the navigational benefits of their installations, the Philippines also openly acknowledged that the buoys are intended to serve as “sovereign markers” that boost the Philippines’ presence within as well as control and administration of the claimed areas.
It’s not the first time that buoys have been used in the South China Sea as a means of demonstrating control and asserting claims over disputed areas. A Vietnamese account from 1988 describes efforts to stop Chinese boats from repeated attempts to install buoys at Whitsun Reef. In 2011, the Philippines accused China of installing a buoy and unloading building materials near Iroquois Reef and Amy Douglas Bank, and removed Chinese steel and concrete markers found at Sabina Shoal. In 2015, Chinese buoys were found by the Philippine Navy at Amy Douglas Bank and later at Scarborough Shoal by Filipino fishers who towed them back to shore. In the East China Sea, China in 2021 installed a giant 15-meter-wide buoy to bolster a network of over 27 buoys that it began building in 2014 to collect data for “rights protection” and to demonstrate Chinese sovereignty in disputed areas.
The capabilities of the devices recently deployed by both China and the Philippines in the Spratly Islands remain unclear, but they likely have some sensing and communications capabilities. The Spanish-made buoys installed by the Philippine Coast Guard are reported to be able to signal to nearby vessels as well as collect and transmit data—presumably automatic identification system (AIS) transmissions—back to shore. This would greatly ease the burden of monitoring the hundreds of Chinese militia boats that regularly deploy to these reefs, since most of those vessels broadcast class-B AIS that can only be monitored at close distance.
China’s description of its devices as navigational beacons suggests the platforms are capable of some form of auditory, visual, radar, or radio signaling to nearby vessels, but no information about their specifications has been released. Their rapid deployment, however, suggests they are likely far less sophisticated than the unmanned Ocean E-Station platforms China has installed in the Paracel Islands and Hainan.
Thus far, neither China nor the Philippines has attempted to remove buoys placed by the other: after speculation that the Philippine buoys at Whitsun and Irving Reef were unaccounted for, a Philippine Coast Guard patrol on June 5 confirmed that all 10 Philippine buoys were still in place. For its part, Vietnam rebuked both the Philippines and China for their deployment of buoys, saying that both violated Vietnam’s sovereignty over the Spratly Islands.
But while the current round of buoy competition appears to be over, tensions are slated to crop up again later this year when the Philippines plans to deploy another round of six buoys in the South China Sea. The locations of these additional buoys have yet to be decided, but likely candidates include Commodore Reef and Second Thomas Shoal, the only two Philippine-occupied reefs that have not yet received a buoy, as well as Scarborough Shoal, a reef 130 miles west of Luzon that is favored by Philippine fishers but over which China has maintained effective control since 2012. The placement of buoys at Irving and Whitsun reefs also sets a precedent for the Philippines to continue placing buoys at unoccupied features within its exclusive economic zone, with Iroquois Reef and Sabina Shoal standing out as possible targets given their frequent attraction of both Chinese militia vessels and Philippine Coast Guard patrols. Given China’s persistent harassment of Philippine Coast Guard resupply missions to Second Thomas Shoal, it will be worth watching their response if the Philippines deploys a sovereignty marker there.