The Malaysia–Thailand border divides the sovereign states of Malaysia and Thailand and consists of a land boundary running for 658 km (409 mi) across the Malay Peninsula and maritime boundaries in the Straits of Malacca and the Gulf of Thailand/South China Sea. The Golok River forms the easternmost 95 km stretch of the land border.
The land border is based on the 1909 treaty between Thailand (then known as Siam) and the British which had started to exert their influence over the northern Malay states of Kedah, Kelantan, Perlis, and Terengganu in the early 20th century, states which were previously under Siamese control. Currently, the international border forms part of the borders of four Malaysian states (Kedah, Kelantan, Perak, and Perlis), and four Thai provinces (Narathiwat, Satun, Songkhla, and Yala).
Malaysia and Thailand have territorial sea and continental shelf boundary agreements for the Straits of Malacca which were signed in 1979 and 1971, respectively. The 1979 agreement also included Indonesia as a signatory as it also determined the common continental shelf border tripoint for the three countries. The 1979 agreement also established the territorial sea boundary in the Gulf of Thailand while a separate memorandum of understanding signed in 1979 established a short continental shelf boundary in the area. The boundary beyond that agreed is disputed because of overlapping claims over the seabed. The overlapping claims led to the establishment of a joint development area in 1990 where both countries agreed to share mineral resources in a 7,250 square km wedge-shaped area.
Land border
The 658-kilometre Malaysia-Thailand land boundary consists of a 552-kilometre section on land running along the watershed of several mountain ranges in northern Peninsular Malaysia and southern Thailand, and 106 kilometres running along the thalweg of the Golok River (Malay: Sungai Golok).
From west to east, the border begins at a point which lies just north of the Perlis River estuary as defined in the schedule of the Anglo-Siamese Treaty of 1909 where the westernmost land boundary terminus was to be at "the most seaward point of the northern bank of the estuary of the Perlis River".
The treaty then states that the border moves northward from this point to the Sayun Range, an extension of the Si Thammarat Mountains of Thailand, for about 15 miles (24 km) before heading eastward along the watershed of Thailand's Lam Yai River and Malaysia's Perlis River towards the ridge of the Kedah-Singgora mountains where it moves southwards along the ridgeline until it reaches the watershed for the Perak and Pattani Rivers. Mountain peaks along this section of the border include Lata Papalang.
The border then moves eastward across the northern part of Peninsular Malaysia's Main Range (Malay: Banjaran Titiwangsa) along the watershed of Malaysia's Perak River and Pergau River (in Kelantan) on one hand, and Thailand's Pattani and Sai Buri Rivers on the other until it reaches Jeli Hill (Malay: Bukit Jeli). Among the mountain peaks located along this section of the border are Kobeh Hill (Malay: Bukit Kobeh), which is the southernmost point of Thailand, and Ulu Titi Basah.
At Bukit Jeli, an 8.5 km stretch of the border remains disputed by both countries (see below).
From Bukit Jeli, the boundary follows the Golok River until the river mouth at Kuala Tabar, a distance of 95 km. The border follows the deepest part or thalweg of the river.
Survey and demarcation Work to survey and demarcate the watershed boundary began on 6 July 1973 and was completed, except for the 8.5 kilometre disputed section at Jeli Hill, on 26 September 1985. As for the Golok River section, work to survey the boundary began on 1 November 2000 and was completed on 30 September 2009.
Barrier In the 1970s, both Malaysia and Thailand constructed walls along their common border, mostly in Perlis/Satun and Perlis/Songkhla as well as Kedah/Songkhla portions of the border to curb smuggling. The walls were of concrete, steel, and topped barbed wire as well as iron fencing at other stretches. As both countries constructed their walls on their own territory, a strip of "no man's land" about 10 m wide was created and this strip of land became a convenient refuge for smugglers (not all smuggling was deterred by the wall) and drug runners.
In 2001, the two countries agreed to construct just one wall along the border which would be just inside Thai territory. The new border wall is 2.5 m high and made of a concrete lower half and steel fencing on the upper half. At the base, barbed wire runs along the length of the wall. The reason given for the construction of the wall was to curb smuggling and encroachment. However, security concerns arising from the South Thailand insurgency in the late 1990s and early 2000s have also been an impetus for the barrier's construction.
Maritime border Malaysia and Thailand share maritime borders in two areas: in the Straits of Malacca and in the Gulf of Thailand/South China Sea.
Straits of Malacca At the western terminus of the land boundary, the 1909 Anglo-Siamese treaty determines the start of the maritime boundary as: With regard to the islands close to the west coast, those lying to the north of the parallel of latitude where the most seaward point of the north bank of the estuary of the Perlis River (the western terminus of the Malaysia-Thailand land boundary) touches the sea shall remain to Siam, and those lying to the south of the parallel shall become British." The island known as Pulau Langkawi, together with all the islets south of the mid-channel between Tarutao and Langkawi, and all the islands south of Langkawi shall become British. Tarutao and the islets to the north of mid-channel shall remain to Siam.
The territorial sea boundary agreement between the two countries signed on 24 October 1979 determined the mid-channel point between Langkawi and Tarutao to be at which was made the eastern starting point of the territorial sea boundary. Both countries also have a continental shelf boundary agreement for this segment of their maritime boundary. The agreement, signed 21 December 1978, included Indonesia as a signatory to enable the establishment of the common tripoint at .
Point Latitude (N) Longitude (E) Remarks Territorial sea border end and turning points 1 6° 28'.5 99° 39'.2 2 6° 30'.2 99° 33'.4 3 6° 28'.9 99° 30'.7 4 6° 18'.4 99° 27'.5 Indonesia-Malaysia-Thailand common point CP 5° 57'.0 98° 1'.5 The border is a straight line connecting the common point with Point 1 below Outer limit border turning point coordinates 1 6° 18'.0 99° 6'.7 The border connects to the common point above via a straight line 2 6° 16'.3 99° 19'.3 3 6° 18'.4 99° 27'.5 This point is the same as Point 4 of the territorial sea border
Gulf of Thailand/South China Sea Agreements
The 1909 Anglo-Siamese Treaty states that the maritime boundary between the two countries as follows: "All islands adjacent to the eastern States of Kelantan and Terengganu, south of the parallel of latitude drawn from the point where the Sungei Golok reaches the coast at a place called Kuala Tabar, shall be transferred to Great Britain, and all islands to the north of that parallel shall remain to Siam."
Subsequently, the two governments signed several agreements over their common maritime boundary in the Gulf of Thailand and South China Sea. The 1973 continental shelf boundary agreement between the two governments only covered the Straits of Malacca segment and did not cover the border in the Gulf of Thailand but on 24 October 1979, an agreement and a memorandum of understanding were signed to determine the common maritime boundary of the two countries in the Gulf of Thailand. The first agreement established the territorial sea boundary from the mouth of the Golok River at to . The MOU established the continental shelf boundary from the northern end-point to with one turning point in between.
The boundary beyond the northern end-point is subject to dispute (see Disputes section below). However, both countries have come to an agreement to put aside the border dispute and allow for the joint exploitation of natural resources of the disputed area. The two countries signed a Memorandum of Understanding for the Establishment of a Joint Authority for the Exploitation of the Resources of the Sea-Bed in a Defined Area of the Continental Shelf of the Two Countries in the Gulf of Thailand on 21 February 1979, followed by an Agreement on the Constitution and Other Matters Relating to the Establishment of the Malaysia-Thailand Joint Authority on 30 May 1990 establishing a joint development area (JDA). Both agreements do not settle disputed maritime border and sovereignty issue of the disputed area and the countries continue staking their overlapping continental shelf claims.
Malaysia's 1979 map and Thailand's EEZ proclamation
In December 1979 just after the two countries signed the MOU on the joint development area, Malaysia published a mapSee map reproduced by the Singapore Ministry of Foreign Affairs in the country's response in the International Tribunal of the Law of the Sea case concerning the reclamation of lands by Singapore in the Straits of Johor . showing its territorial sea and continental shelf and continued to assert its sovereignty over the entire joint development area. Malaysia's continental shelf boundary on the map corresponds with the western and northern limit of the joint development area.
On 16 February 1988, Thailand issued a royal proclamation to establish its exclusive economic zone boundary with Malaysia, establishing the limits of its claims in the disputed area. The boundary follows the eastern boundary of the Joint Development Area.
A small triangle in the northern portion of the joint development area is also subjected to an overlapping claim by Vietnam. In 1999, Malaysia, Thailand, and Vietnam agreed to apply the joint development principles to this area. See section below.
Point Latitude (N) Longitude (E) Remarks Territorial sea border end and turning points 1 6° 14'.5 102° 5'.6 2 6° 27'.5 102° 10'.0 Continental shelf border end and turning points 1 6° 27'.5 102° 10'.0 Same point as northern terminus of the territorial sea border, also Point 47 on Malaysia's 1979 continental shelf claim map 2 6° 27'.8 102° 9'.6 Same as Point 46 on Malaysia's 1979 continental shelf claim map 3 6° 50'.0 102° 21'.2 Same as Point 45 on Malaysia's 1979 continental shelf claim map Continental shelf border end and turning points claimed by Malaysia 45 06° 50'.0 102° 21'.2 Same point as the northern terminus of the agreed continental shelf border; also Point A of Joint Development Area. 44 07° 10'.25 102° 29'.0 Same as Point B of Joint Development Area 43 07° 49'.0 103° 02'.5 Same as Point C of Joint Development Area Exclusive economic zone border end and turning points claimed by Thailand 1 6° 14'.5 102° 5'.6 Southern terminus of territorial sea boundary 2 6° 27'.5 102° 10'.0 Northern terminus of territorial sea boundary and southern terminus of agreed continental shelf border; same as Point 47 on Malaysia's 1979 map 3 6° 27'.8 102° 9'.6 Same as Point 46 on Malaysia's 1979 map 4 06° 50'.0 102° 21'.2 Northern terminus of the agreed continental shelf border; same as Point 45 on Malaysia's 1979 map; also Point A of Joint Development Area. 5 06° 53'.0 102° 34'.0 Same as Point G of Joint Development Area 6 07° 03'.0 103° 06'.0 Same as Point F of Joint Development Area 7 07°20'.0 103° 39'.0 Same as Point E of Joint Development Area 8 07° 22'.0 103° 42'.5 Same as Point D of Joint Development Area, located on Malaysia's continental shelf border between Point 43 and Point 42 on 1979 map
History