Brunei–Malaysia border which are defined by agreements, from west to east, are as follows: Brunei and Malaysia in an Exchange of Letters on 16 March 2009, agreed to affirm the five agreements. The two countries also agreed to use the watershed principle to determine the remaining undelimited portions of the border. Brunei's maritime boundary with Malaysia until the 100 fathom isobath was inherited from the Sarawak (Definition of Boundaries) Order in Council 1958 No 1518 and the North Borneo (Definition of Boundaries) Order in Council 1958 No 1517, both of which defined the boundary between Brunei on the one hand, and Sarawak
Indonesia–Malaysia border of the two countries under the 1969 continental shelf boundary. The border in the Celebes Sea is subject to dispute between the two countries. Part of the dispute was settled by the judgement of the International Court of Justice in the Ligitan and Sipadan Case in 2002 and is now awaiting delimitation between the two countries. The two countries however still have overlapping claims over the continental shelf which Indonesia refers to as Ambalat. There are numerous sea transport crossings between Indonesia and Malaysia, mostly between Indonesia's Sumatra island and Peninsula Malaysia but also between the Indonesian province of North