Which Countries Border Brunei?

Small nation of Brunei on the island of Borneo in Southeast Asia.
Small nation of Brunei on the island of Borneo in Southeast Asia.

Brunei is an Islamic sultanate located in Southeast Asia on the island of Borneo. The small nation has a coastline with the South China Sea and is surrounded by its bigger neighbor, Malaysia. Brunei consists of two disconnected territories that occupy a total land area of 2,226 square miles and are separated by the state of Sarawak. The segment to the west is significantly larger than the part on to the east and is home to the nation’s capital of Bandar Seri Begawan. The nation gained its independence from the British in 1984 and has since seen its population rise to 428,000.

History of the Empire of Brunei

At the height of the Sultanate’s rule in the 15th century, Brunei occupied vast territory on the island of Borneo and territory to the south of the Philippines. The sultanates gradually declined and subsequently lost most of the territory due to internal succession conflict, piracy, and expansion of colonial powers such as the British. The 19th century witnessed the drastic decline of the sultanate after it ceded Sarawak to an adventurer by the name James Brooke in exchange for his services in crushing the internal rebellion and managing the pirate menace off the coast. With his help, the Sultan of Brunei was restored to his throne. The Sultan accorded him the title of the White Rajah and claim over the Sarawak territory.

Brunei went under the protection of the British as a protectorate in 1888. The Sultanate subsequently lost more territory to the James Brooke Kingdom of Sarawak through lease and seizure. This loss of territory eventually led to the separation of Brunei's territory when the Kingdom of Sarawak seized the Pandaren district of Brunei. The British did not intervene, and the Sultan of Brunei was forced to appeal to the British to prevent the further encroachment of his territory.

Establishment of Brunei’s Current Land Borders

After the declaration of independence from the British in 1984, the sultanate has had some disputes with its larger neighbor for several years. Almost half of the 299-mile border with Sarawak has over the years been defined by various agreements with a section of the boundary remaining undefined. Some of the sections defined by the agreements include the border as it runs along Pandaruan River (1920), the border between the Baram and Belait rivers, the border between the coast and the Pagalayan Canal (1931), and the border to the east of Temborong (1931). Other areas defined include the border between the Brunei Bay and a point to the west of Godang hill which is demarcated along the Limburg Rivers and the watershed of Brunei (1933) and the border between the Teraja Hills and the Palagayan Canal (1939). The agreements were affirmed by the exchange of letters in March 2009.

Brunei’s Maritime Border

The maritime borders of Brunei and Malaysia are derived from the British colonial Order in Council from the British Boundaries Act of 1895. Based on the Order in Council, Malaysia was given claim to 100-fathom isobaths. The British Orders of the Council are still used by Brunei to claim the continental shelf. The maritime border of Brunei is divided into the western sector, Western Brunei Bay sector, and the Eastern sector. The western sector consists of the seaward extension from the terminus of Brunei’s western boundary with the state of Sarawak. The western Brunei Bay Sector helps define the boundary when one is headed to Bartang Limbang which starts at the Pandaren River estuary and runs to Pulau Silamak. The Eastern sector extends from the terminus of Brunei’s Temburong boundary with Sarawak and runs up to the Brunei-Sabah-Sarawak point as indicated by the Order in Council 1958.

Brunei Bay

The boundaries of the Brunei Bay remained un-addressed by the exchange of letters in 2009 with the only mention of the issue coming up in 2014 during the Annual Leaders Consultation where a joint statement was released attempting the demarcation.

Continental Shelf Claim

The Sultanate of Brunei currently claims the continental shelf spanning 200 nautical miles into the sea with the borders of the claimed area running straight from the points of termination of its borders on its coast. The claims are based on Order in Council 1958. The Sultanate also claims an eastern boundary that runs from the 100-fathom isobath and a western border that runs from similar 100-fathom isobaths with the limits to the Exclusive Economic Zone extending between the terminal points. The continental shelf claim included waters that surrounded the Spratly Islands. Brunei, however, does not claim the island in the South China Sea but does claim the Louisa Reef which is under the control of Malaysia. Territorial disputes in 1979 with Malaysia over Brunei’s claim to the continental shelf were finally settled in 2009 in an exchange of letters that affirmed Brunei's claims.

Pre-colonial Malaysia-Brunei Relations

In 1962, members of the North Kalimantan National Army, which was opposed to the monarchy in Brunei under the British protectorate, began a struggle with the aim of preventing the absorption of the sultanate into the Federation of Malaysia. The militia was influenced by the BPP (Brunei People’s Party) and was supported by Indonesia. The militia conducted attacks on oil installations, government outposts, and police stations. The revolt, however, was short-lived and influenced the Sultans decision not to allow the sultanate to become part of Malaysia. The rebellion also marked the initial confrontation between Malaysia and Indonesia.

Brunei’s Relations with Malaysia

The two nations have enjoyed good relation during the post-colonial period after resolving the border disputes between the two nations through an amicable process. The strong relations between the two nations are based on rich cultural links between the nations dating back to the Brunei Empire when parts of Malaysia were part of the Kingdom. The two nations, however, had a more profound disagreement over two oil blocks off the coast which were claimed by Malaysia. The dispute was subsequently resolved between the two nations hence guaranteeing continued positive bilateral relations.

Brunei’s Security

With relatively good relations with its neighbor, Brunei maintains a small Armed Force that consists of an army group, navy, and air force units that are substantially equipped. Security is further supplemented by the Royal Brunei police and Ghurka reserve unit. The nation also has a battalion of British forces on its territory to protect petroleum and gas fields.


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