Gen Chalermpol Srisawat, the chief of Thailand's defence forces, has left for the United States on an official visit invited by the Pentagon, a source said on Saturday.
The trip is the first of its kind since the Covid-19 pandemic struck about two years ago, said the source.
Gen Chalermpol, along with Gen Natapol Boonngam, the military chief of staff, will stay in the United States until Dec 20. They left Thailand on Saturday.
Gen Chalermpol will be in Washington, DC to meet Gen Mark A Milley, a US Army general who serves as the 20th chairman of the Joint Chiefs of Staff, and US Secretary of Defense Lloyd J Austin III.
Their meetings are aimed at strengthening military and security ties between Thailand and the United States, said the source, adding that a plan to organise next year's Cobra Gold joint Thai-US military exercise is expected to be among the topics discussed.
Gen Chalermpol will also visit Arlington National Cemetery for a remembrance service before leaving for Washington State where he will meet the chief of the US National Guard.
Gen Chalermpol will focus on security cooperation and fostering international relations through military mechanisms, said the source.
He will also travel on to New York City for a meeting with the United Nations deputy secretary to discuss a plan to send more engineering soldiers to support the UN's mission in South Sudan.
Before leaving the US at the end of the trip, Gen Chalermpol is expected to meet Thai military students at the US Military Academy West Point.