It was ASEAN’s first expansion since the 1990s and was more than a decade in the making.
“For the people of Timor Leste this is not only a dream realized, but a powerful affirmation of our journey — one marked by resilience, determination and hope,” he said.ASEAN opens: Key moves to watch
The ceremony marked the opening of ASEAN’s annual summit, followed by two days of high-level engagements with key partners including China, Japan, India, Australia, Russia, South Korea and the US.
US President Donald Trump arrived Sunday in his first trip to Asia since returning to the White House, and was expected to sign a trade deal with Malaysia later in the day.
Trump was also to take part in the signing of an agreement between Cambodia and Thailand, expanding a ceasefire that halted their border conflict earlier this year.
Chinese Premier Li Qiang, Canadian Prime Minister Mark Carney and Japan’s newly inaugurated Prime Minister Sanae Takaichi are among more than a dozen other leaders expected to be on hand.
Expanding ASEANThe last country to join ASEAN was Cambodia in 1999.
East Timor, wedged between Indonesia and Australia, was a Portuguese colony for over four centuries before declaring independence in 1975.
Indonesia invaded nine days later, beginning a brutal 24-year occupation that claimed tens of thousands of lives through conflict, famine and disease. A UN-supervised referendum in 1999 paved the way for independence, which was formally restored in 2002.
Today it is led by two independence heroes, Prime Minister Gusmao and President Jose Ramos-Horta, who won the Nobel Peace Prize in 1996.
Initially, the idea of bringing East Timor into ASEAN was met with skepticism by several other members, and even though that was overcome, Joanne Lin, co-coordinator of the ISEAS–Yusof Ishak Institute’s ASEAN Studies Centre in Singapore, said adding the nation is “not without challenges.”
“Timor-Leste’s administrative and institutional capacity still lags behind most ASEAN members, and full participation will require sustained technical and financial support from the secretariat and member states,” she said. “But its inclusion also brings new energy and perspectives — especially on issues like youth empowerment, democratic governance and small-state diplomacy.”
For East Timor, ASEAN membership gives it access to the bloc’s free trade deals, investment opportunities and a broader regional market.
East Timor applied for membership in 2011 and was granted observer status in 2022.
“For us this new beginning brings immense opportunity in trade, investment, education and the digital economy — we are ready to learn, innovate and uphold good government,” Gusmao said.
“This is not the end of a journey, this is a beginning of an inspiring new chapter.”
