Lockheed said Britain will use the short takeoff/vertical landing F-35 Lightning II training and operational tests.
The aircraft for Britain, known as the BK-1, is slated for delivery next year after completing functional fuel system checks, ground tests and flight tests.
"This first F-35 for the first international program partner is symbolic of the proud partnership we share with the United Kingdom," said F-35 Executive Vice President and General Manager of Program Integration Tom Burbage.
"Working together in a spirit of collaboration, we are providing the men and women of the (British air force and navy) with unmatched fifth-generation capabilities, while delivering advanced technology sector jobs to the U.K."
International partners in the plane's development are Britain, Italy, the Netherlands, Turkey, Canada, Australia, Denmark and Norway.
The F-35 combines advanced stealth capabilities with the speed and maneuverability. The plane is being developed by Lockheed and its industrial partners, Northrop Grumman and BAE Systems.
Israel last year picked the F-35A and is to receive the aircraft through the U.S. government's Foreign Military Sales process. Japan and South Korea are also considering purchase of the aircraft.