The highest ranking US officer to visit Thailand since the 2014 coup will attend the Cobra Gold war games next month in what the Thai army hailed on Wednesday as a sign of improving relations.
The US embassy confirmed that Admiral Harry Harris, the head of Pacific Command, would open Cobra Gold on Feb 14. More junior officers attended the exercise in the past two years.
Harris' attendance was planned before the inauguration of US President Donald Trump, whose policy moves on Asia are closely watched after signals of potential confrontation with China over trade, Taiwan and claims in the South China Sea.
The United States scaled down its presence at Cobra Gold, Asia's largest annual multinational military exercise, as one of the former US administration's measures to pressure the Thai government to restore democracy.
The US embassy said Cobra Gold would only return to its original scope and scale once Thailand restores democracy.
Relations have since improved as the junta has taken steps towards holding elections - and as Thailand has grown closer to dominant regional power China.
"We are eager to see our cooperation fully resume with the restoration of a democratically elected civilian government," said Melissa Sweeney, a spokeswoman at the US embassy.
The United States will send 3,500 personnel to Cobra Gold, even fewer than last year.
Thailand's army said that Harris's attendance at Cobra Gold sent an important signal.
"It is not common for an officer of Admiral Harris' rank to attend these sorts of events," said Thanchaiyan Srisuwan, the supreme commander.
"It is a good signal for Thai-American relations and shows that the US has given importance to this region and this exercise," said Gen Thanchaiyan.
Thailand has hosted the war games since they began in 1982. This year's event will be attended by 8,333 personnel from 29 countries.