No injuries were reported.
The two fighter planes from the 12th Fighter Squadron, home-stationed at Elmendorf, Alaska, "inadvertently made contact over water" at around 2:45 pm (0545 GMT), the US Air Force said in a statement.
The planes, engaged in a drill off the coast of Okinawa, were damaged in the accident, but both recovered safely to the base, "avoiding populated areas by safely using an over-water approach", it said.
A Kadena Air Base spokesman said there the crew was not injured, adding that investigation into the case is now under way.
Japan's public broadcasting network NHK showed footage of damaged vertical fins on one of the planes and damage to a wing and a horizontal fin on the other.