The island groups include: The geology has been extensively studied because of exploitable resources such as oil and gas and is complex.

The northeast trade winds bring a winter dry season, and December is the lowest-rainfall month (3.3 mm (0.13 in)).

The islands are feeding and nesting sites for large numbers of seabirds, including the streaked shearwater (Calonectris leucomelas), brown booby (Sula leucogaster), red-footed booby (S. sula), great crested tern (Sterna bergii) and white tern (Gygis alba).

In the 19th century, as a part of the occupation of Indochina, France claimed control of the Spratlys until the 1930s, exchanging a few with the British.

The People's Republic of China, founded in 1949, claimed the islands as part of the province of Canton (Guangdong), and later of the Hainan special administrative region.

The South China Sea Islands were discussed from the 4th century BC in the Chinese texts Yizhoushu, Classic of Poetry, Zuo Zhuan, and Guoyu, but only implicitly as part of the "Southern Territories" (Chinese: 南州; pinyin: Nán Zhōu) or "South Sea" (南海, Nán Hǎi).

The naming campaign is intended to consolidate China's sovereignty claim over Sansha (三沙),[13] a city which includes islands from the Xisha (Paracel), Nansha (Spratly and James Shoal) and Zhongsha (中沙, Zhōngshā; Macclesfield Bank, Scarborough Shoal, and others) groups.

There are minerals, natural gas and oil deposits on the islands and under their nearby seafloor, also an abundance of sea life, such as fish, animals and vegetation, traditionally exploited as food by all the claimant nations for thousands of years—mostly without disputes that could risk war.

In 1958, the People's Republic of China (PRC) issued a declaration defining its territorial waters within what is known as the nine-dash line which encompassed the Spratly Islands.

Regarding this letter, there have been many arguments on its true meaning and the reason why Phạm Văn Đồng decided to send it to Zhou Enlai.

In an interview with BBC Vietnam, Dr. Balázs Szalontai provided the following analysis of this issue: The general context of the Chinese declaration was the United Nations Conference on the Law of the Sea, held in 1956, and the resulting treaties signed in 1958, such as the Convention on the Territorial Sea and Contiguous Zone.

The Soviet Union did not give any substantial support to Vietnamese reunification, and neither South Vietnamese leader Ngo Dinh Diem nor the U.S. government showed readiness to give consent to the holding of all-Vietnamese elections as stipulated by the Geneva Agreements.

This is why Phạm Văn Đồng felt it necessary to take sides with China, whose tough attitude toward the Asian policies of the U.S. offered some hope.

Still, it is true that in this bilateral territorial dispute between Chinese and Vietnamese interests, the DRV standpoint, more in a diplomatic than a legal sense, was incomparably closer to that of China than to that of South Vietnam.

[15][citation needed]It was also argued that, Phạm Văn Đồng who represented North Vietnam at that time had no legal right to comment on a territorial part which belonged to the South Vietnam represented by Ngo Dinh Diem.

Therefore, the letter has no legal value and is considered as a diplomatic document to show the support of the government of North Vietnam to the PRC at that time.

The Philippines claim most of the Spratlys and calls them the Kalayaan Group of islands, and they form a distinct municipality in the province of Palawan.

It clarified that it would not "...rule on any question of sovereignty over land territory and would not delimit any maritime boundary between the Parties".