January 30, 2016– USS Curtis Wilbur transits within 12 nautical miles of Triton Island in the Paracel Islands.
May 10, 2016– USS William P. Lawrence transits within 12 nautical miles of Fiery Cross Reef in the Spratly Islands.
October 21, 2016– transits near Triton Island and Woody Island in the Paracel Islands. Although this was not within the 12 nautical mile boundaries of each island, it did contest the excessive baseline claims by China.
The Chinese People's Liberation Army had established a significant presence in vicinity of the Paracel Islands through their own FONOPs prior to their confrontation with Vietnam during the Battle of the Paracel Islands in 1974. According to Chinese Law, specifically the 1992 Territorial Sea/Contiguous Zone Law, China has full ownership of the Paracel Islands, which has created tension with the Socialist Republic of Vietnam and the Republic of China. In 1983, President Ronald Reagan declared that the U.S. would not ratify the 1982 Third United Nations Convention on the Law of the Sea. China signed and ratified UNCLOS III in 1996. Nevertheless, the U.S. Navy- under the Obama Administration- has operated in accordance with UNCLOS III with the use of innocent passage, proper communications, and respect for nations' territorial waters. United States Pacific Fleet vessels spent a combined total of 700 days in the South China Sea during 2015 alone. This includes vessels assigned to Carrier Strike Group 5, which included the until the summer of 2015, at which point the USS Ronald Reagan took its place in the homeport of Yokosuka, Japan after a hull swap in San Diego, CA.
On July 12, 2016, the Hague's International Tribunal for the Law of the Sea ruled in the Permanent Court of Arbitration that the People's Republic of China's claims were excessive and violated the Republic of Philippines' sovereignty when they. The Philippines filed the case on 22 January, 2013 with a strong backing from President Benigno Aquino. Although the Obama Administration did not overtly back the Philippines in the case, President Obama and Secretary John Kerry did publicly express support for the right of sovereign nations to follow international law and norms and to dispute disagreements in the legal and appropriate forums, although emphasizing that since the US is not a claimant they are a neutral party. China declared that it did not recognize the jurisdiction of the tribunal prior to proceedings, and requested the Philippines to do the same. Meanwhile, the Obama Administration continued to urge all nations to follow international law and abide by the ruling for the remainder of Obama's presidency.
Claimants to the South China Sea island disputes include Brunei, China, Indonesia, Malaysia, Philippines, Taiwan and Vietnam. Although the US is neutral in the disputes, the American military participates in training exercises with each claimant. During the 2016 Arbitration ruling, the Chinese Navy's CNS Changdao and divers participated in RIMPAC 16. Exercise CARAT and Balikatan are among several annual exercises involving these same nations.