Natuna Sea in the context of "Riau Islands Province"

The Riau Islands (Indonesian: Kepulauan Riau; Jawi: كڤولاوان رياو) is a province of Indonesia consisting of a group of islands located in the western part of the country. It was established in 2002 after being separated from the neighboring Riau Province. The capital of the province is Tanjung Pinang, while the largest city is Batam. It shares a maritime border with Riau and Jambi to the west, Bangka Belitung Islands to the south, Singapore to the northeast, Malaysia and West Kalimantan to the east, and Vietnam and Cambodia to the north. It comprises a total of 2,408 islands (1,798 having names) scattered between Sumatra, Malay Peninsula, and Borneo including the Riau Archipelago. Situated on one of the world's busiest shipping lanes along the Malacca Strait and the Natuna Sea (South China Sea), the province shares water borders with neighboring countries such as Singapore, Malaysia, and Brunei. The Riau Islands also have relatively large potential mineral resources and energy, as well as marine resources.

The Riau Islands have played a significant role in the maritime history and civilization of the Nusantara region. Between the 7th and 13th centuries, the area was influenced by the powerful Srivijaya Empire, a major maritime kingdom that controlled trade routes along the Malacca Strait. Evidence of Srivijaya's influence in the Riau Islands can be seen from the discovery of the Pasir Panjang Inscription [id] in Karimun Regency, which shows the existence of religious practices through Buddha's footprints, indicating early settlement and the spread of Buddhism long before the arrival of Islam.

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).

Berhala Strait is a strait which separates the island of Sumatra and Singkep in the Natuna Sea (South China Sea), Indonesia.

Berhala island in the strait, attribution has been contested by Riau Islands and Jambi province.