It was the first South Korean military exercises conducted near the islands since December and since South Korean President Yoon Suk-yeol took office in May.
The U.S. destroyer sailed near the contested Spratly Islands, days after China claimed to have expelled the same vessel from waters near the disputed Paracel islets.
Chinese vessels have now been spotted near the islands, including in the so-called contiguous zone outside Japanese waters, for 81 days in a row, according to the coast guard.