Karimata Strait in the context of "Bangka Strait"

The South China Sea is a marginal sea of the Western Pacific Ocean. It is bounded in the north by South China, in the west by the Indochinese Peninsula, in the east by the islands of Taiwan and northwestern Philippines (mainly Luzon, Mindoro, and Palawan), and in the south by Borneo, eastern Sumatra, and the Bangka Belitung Islands, encompassing an area of around 3,500,000 km (1,400,000 sq mi). It communicates with the East China Sea via the Taiwan Strait, the Philippine Sea via the Luzon Strait, the Sulu Sea via the straits around Palawan, the Java Sea via the Karimata and Bangka Straits, and directly with the Gulf of Thailand. Additionally, the Gulf of Tonkin is part of the South China Sea.

$3.4 trillion of the world's $16 trillion maritime shipping passed through the South China Sea in 2016. Oil and natural gas reserves have been found in the area. The Western Central Pacific accounted for 14% of the world's commercial fishing in 2010.

The Java Sea (Indonesian: Laut Jawa, Javanese: Segara Jawa) is an extensive shallow sea on the Sunda Shelf, between the Indonesian islands of Borneo to the north, Java to the south, Sumatra to the west, and Sulawesi to the east. Karimata Strait to its northwest links it to the South China Sea. Although generally considered to be a part of the western Pacific Ocean, the Java Sea is occasionally considered to be a part of the Indian Ocean.

Sumatra (/sʊˈmɑːtrə/) is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the sixth-largest island in the world at 482,286.55 km (182,812 mi.), including adjacent islands such as the Simeulue, Nias, Mentawai, Enggano, Riau Islands, Bangka Belitung and Krakatoa archipelago.

Sumatra is an elongated landmass spanning a diagonal northwest–southeast axis. The Indian Ocean borders the northwest, west, and southwest coasts of Sumatra, with the island chain of Simeulue, Nias, Mentawai, and Enggano off the western coast. In the northeast, the narrow Strait of Malacca separates the island from the Malay Peninsula, which is an extension of the Eurasian continent. In the southeast, the narrow Sunda Strait, containing the Krakatoa archipelago, separates Sumatra from Java. The northern tip of Sumatra is near the Andaman Islands, while off the southeastern coast lie the islands of Bangka and Belitung, Karimata Strait and the Java Sea. The Bukit Barisan mountains, which contain several active volcanoes, form the backbone of the island, while the northeastern area contains large plains and lowlands with swamps, mangrove forest and complex river systems. The equator crosses the island at its centre in West Sumatra and Riau provinces. The climate of the island is tropical, hot, and humid. Lush tropical rain forest once dominated the landscape.

The Bangka Belitung Islands (Indonesian: Kepulauan Bangka Belitung) is a province of Indonesia. Situated off the southeastern coast of Sumatra, the province comprises two main land masses — the islands of Bangka and Belitung — and numerous smaller islands. Bangka Belitung is bordered by the Bangka Strait to the west, the Natuna Sea to the north, the Java Sea is to the south and the Karimata Strait to the east; the two principal islands are separated by the Gaspar Strait, within which lie lesser islands such as Lepar, Pongok (or Liak) and Mendanau.

The province's capital and largest city is Pangkalpinang. The province shares maritime borders with South Sumatra to the west, Riau Islands to the north, Banten, the Special Capital Region of Jakarta, West Java, and Central Java to the south, and West Kalimantan to the east. Bangka Belitung covers a land area of 16,690.13 km (6,444.10 sq mi) and had a population of 1,455,678 according to the 2020 census; the official estimate as at mid 2024 was 1,531,530 (comprising 786,010 males and 745,520 females).

The Natuna Sea (Indonesian: Laut Natuna) is an extensive shallow sea located around the Natuna Regency, extending south of the Riau Islands, east of the Lingga Regency and west of Borneo, to the Bangka Belitung Islands. The islands of the Badas and Tambelan Archipelago are located at its center. Mostly located within Indonesian territorial waters, it is the southernmost portion of the South China Sea, and geologically part of Sunda Shelf. It communicates with the Java Sea to its southeast via the Karimata and Gaspar Strait east and west of Belitung, and with the Strait of Malacca to the west via the Berhala and Singapore Strait.

The International Hydrographic Organization (IHO), in its Limits of Oceans and Seas, 3rd edition (1953), does not list a Natuna Sea. Instead, the area encompassed by the Natuna Sea is considered the southern portion of the South China Sea. The 1986 draft of the IHO's Limits of Oceans and Seas proposed the Natuna Sea, which extends south from the Natuna and Anambas Islands to the Belitung Islands.

Tambelan Islands is a group of 68 islands off the west coast of West Kalimantan (Borneo), Indonesia, just north of the equator. The archipelago is located on the north opening of Karimata Strait which separates Borneo and Belitung island. Geographically it is part of the Tudjuh Archipelago, and administratively forms a district (kecamatan) of Bintan Regency within the Riau Islands Province. It covers a land area of 90.4 km and had a population of 4,960 in mid 2022. Major islands include Big Tambelan (Tambelan Besar), Mendarik, Uwi, Benua, and Pejantan. The islands are divided into eight administrative villages (kelurahan) - Batu Lepuk, Kampung Hilir, Kampung Melayu, Kukup, Pengikik, Pulau Mentebung, Pulau Pinang and Teluk Sekuni. As a historical side note; It was the first Dutch territory captured by the Japanese in World War 2.