Treaty on Certain Maritime Arrangements in the Timor Sea

Officially called the Treaty between Australia and the Democratic Republic of Timor-Leste on Certain Maritime Arrangements in the Timor Sea (CMATS),[1] the treaty provides for the equal distribution of revenue derived from the disputed Greater Sunrise oil and gas field between Australia and East Timor.

CMATS was signed in Sydney on January 12, 2006, by Australian Foreign Affairs Minister Alexander Downer and his East Timorese counterpart José Ramos-Horta.

[3] Following a resolution at the Permanent Court of Arbitration, CMATS was succeeded in 2018 by the Treaty Between Australia and the Democratic Republic of Timor-Leste Establishing Their Maritime Boundaries in the Timor Sea.

[7] Both countries will also not start any proceedings against the other before any court on issues related to maritime boundaries or delimitation in the Timor Sea.

[13] This is taken to allow Australia to continue with petroleum exploration and exploitation activities in the Laminaria-Coralina and other fields it claims to be located in its territorial waters as a result of the Agreement between the Government of the Commonwealth of Australia and the Government of the Republic of Indonesia Establishing Certain Seabed Boundaries in the Area of the Timor and Arafura Seas, Supplementary to the Agreement of 18 May 1971 (See Australia-Indonesia border page).

[18][19] According to this position, if a maritime boundary were established along the median line between the coasts of the two countries, the current prevailing practice, all of Greater Sunrise would be in Timor-Leste's territory.

[23] East Timor shall have "sovereign rights" over the water column north of the southern border of the Joint Petroleum Development Area established under the Timor Sea Treaty while Australia gains "sovereign rights" over the water column south of the line.

[25] The parties agree not to re-determine the apportionment ratio of the Greater Sunrise field for the period the treaty is in force.

[27] No development plan had been approved by 23 February 2013, six years after CMATS came into force, and Timor-Leste was weighing whether to give notice of termination.

CMATS was tabled in the Australian parliament on the first sitting day of 2007 on February 6, 2007, and on February 22, 2007, just before the exchange of notes with East Timor, Minister for Foreign Affairs Alexander Downer wrote to inform the parliament's Joint Standing Committee on Treaties of his decision to invoke the national interest exemption, to speed up ratification of the treaty by not first referring it to the Joint Committee.