Real-time simulation is an integral part of the Vehicle Systems and Mission Systems design and risk reduction processes for the three variants of the Joint Strike Fighter (JSF), or F-35, aircraft-Conventional Take-Off and Landing (CTOL), Short Take-Off and Vertical Landing (STOVL), and Carrier Variant (CV). The JSF Program is relying on increased use of modeling and simulation to reduce verification cost and schedule. The F-35 Lockheed Martin/Northrop Grumman/BAE SYSTEMS team utilizes the unique motion capabilities of the NASA Ames Vertical Motion Simulator (VMS) for control law and pilot-vehicle interface design maturation and evaluation. The first in a series of motion-based tests was conducted in February and March 2004 to (1) evaluate flying qualities characteristics where high-fidelity motion is most beneficial, (2) identify design solutions for stressing, land-based and shipboard landings, and (3) mature STOVL control laws. Complex hardware and software were successfully integrated and tested to leverage sound design decisions. During the three-week motion experiment, eight pilots flew approximately 1,360 data runs. The investigative team consisted of personnel from BAE SYSTEMS, Corsair Training Systems, JSF Joint Program Office, Lockheed Martin Aeronautics Company (LM Aero), Northrop Grumman, National Aeronautics and Space Administration (NASA) Ames Research Center, Northrop Grumman Information Technology (IT), United Kingdom (UK) Ministry of Defense and QinetiQ. This paper discusses real-time simulation usage for F-35 control law and pilot-vehicle interface design. Results from the February/March 2004 NASA Ames VMS simulation, as well as preliminary results from LM Aero's-Fort Worth, TX motion-based simulator, are summarized. Plans for real-time motion simulation in (1) additional STOVL control law maturation activities and (2) verification tests in preparation for STOVL first flight are also presented.