Ream Naval Base faces the Gulf of Thailand, adjacent to the South China Sea, where China has aggressively asserted its claim to virtually the entire strategic waterway.
China had signed a secret agreement to allow its military to use the base, citing U.S. and allied officials familiar with the matter.
Chinese Foreign Minister Wang Yi also took a swipe at previous Australian governments describing the Pacific islands as being in the country's 'backyard'.
Biden passed on visiting the demilitarized zone on the North and South border, a regular stop for U.S. presidents when visiting Seoul.
Turkey's state-run news agency said the United States is setting up two military bases and has increased its presence in the Manbij region of northern Syria.