Currently, the bilateral border passes through 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.

[1] 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".

[3] 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.

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.

[citation needed] Malaysia and Thailand share maritime borders in two areas: in the Straits of Malacca and in the Gulf of Thailand/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[5] and a memorandum of understanding[7] were signed to determine the common maritime boundary of the two countries in the Gulf of Thailand.

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 map[8] 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.

[9] A small triangle in the northern portion of the joint development area is also subjected to an overlapping claim by Vietnam.

The border between Thailand or Siam and the sultanates of the Malay Peninsula (Peninsular Malaysia today) has varied throughout history.

The Malay states immediately to the south, namely Perak and Pahang were independent sultanates until the British started asserting influence over them in the late 1800s.

Thailand regained influences of the Kedah, Kelantan, and Terengganu during World War II when the Japanese handed them over to the kingdom, thus moving the Malay States-Siamese border southwards again.

Malaysia's former Foreign Minister Syed Hamid Albar was quoted as saying that the failure was because of the inability to reach a consensus over a formula to solve the dispute.

In 1999, Malaysia, Thailand and Vietnam reached an agreement based on the principle of joint development for the area where the three countries have overlapping claims.