Washington worries that China has built up the islands with the aim of extending its military reach in the South China Sea.
The patrols would be just weeks ahead of a series of Asia-Pacific summits President Barack Obama and Chinese President Xi Jinping are expected to attend in the second half of November.
Xi surprised U.S. officials after a meeting with Obama in Washington last month by saying that China had “no intention to militarize” the islands.
Even before that, however, satellite photographs had shown the construction of three military-length airstrips by China in the Spratlys, including one each on Mischief and Subi reefs.
Some U.S. officials have said that the plan for patrols was aimed in part at testing Xi’s statement on militarization.
In May, the Chinese navy issued eight warnings to the crew of a U.S. P8-A Poseidon surveillance aircraft that flew near the artificial islands but not within the 12-mile limit, reported CNN, which was aboard the U.S. aircraft.
That same month, the USS Fort Worth, a littoral combat ship, “encountered multiple” Chinese warships during a patrol in the Spratly archipelago, the U.S. Navy said at the time. It did not go into detail.
In 2013, Obama ordered two B-52 bombers to fly through an Air Defense Identification Zone that China established in the East China Sea over territory contested with Japan.
Pentagon officials say the United States regularly conducts freedom-of-navigation operations around the world to challenge excessive maritime claims.
In early September, China sent naval vessels within 12 miles of the Aleutian Islands off Alaska. China said they were there as part of a routine drill following exercises with Russia.