Ambassador to Timor-Leste

  • Media release
20 December 2021

Today I announce the appointment of Mr William Costello as Australia's next Ambassador to Timor-Leste.

Australia and Timor-Leste are close neighbours and partners with a deep and enduring bilateral relationship, underpinned by a shared history and strong people-to-people links.

The entry into force of our historic Maritime Boundary Treaty in 2019 opened a new chapter in our relationship. In 2022, we will celebrate the 20th anniversary of the restoration of Timor-Leste's independence and the establishment of our diplomatic relations.

We are working in partnership with Timor-Leste to support the country's COVID‑19 response, and to promote economic recovery, infrastructure and skills development. We are also strengthening our security cooperation, including by providing two Guardian class patrol boats to Timor-Leste in 2023 under our Pacific Maritime Security Program. Australia strongly supports Timor-Leste's ambition to join the Association of Southeast Asian Nations (ASEAN).

Mr Costello is a senior career officer with the Department of Foreign Affairs and Trade and was most recently Assistant Secretary, Labour Mobility and Economic Growth, Office of the Pacific. He has previously served overseas in Washington, Port Moresby, Manila, and Phnom Penh. In Canberra he has held senior leadership positions across a range of regional and development assistance roles.
Mr Costello holds a Master of Public Policy from the Australian National University, and a Bachelor of Applied Science from Canberra College of Advanced Education.

I thank outgoing Ambassador Peter Roberts for his contributions to advancing Australia's interests in Timor-Leste since 2018.

Media enquiries

  • Minister's office: (02) 6277 7500
  • DFAT Media Liaison: (02) 6261 1555