With the intent of improving simulation tools, a 1/50th-scale floating wind turbine atop a TLP was designed based on Froude scaling by the University of Maine under the DeepCwind Consortium. This platform was extensively tested in a wave basin at MARIN to provide data to calibrate and validate a full-scale simulation model. The data gathered include measurements from static load tests andfree-decay tests, as well as a suite of tests with wind and wave forcing. A full-scale FAST model of the turbine-TLP system was created for comparison to the results of the tests. Analysis was conducted to validate FAST for modeling the dynamics of this floating system through comparison of FAST simulation results to wave tank measurements. First, a full-scale FAST model of the as-tested scaledconfiguration of the system was constructed, and this model was then calibrated through comparison to the static load, free-decay, regular wave only, and wind-only tests. Next, the calibrated FAST model was compared to the combined wind and wave tests to validate the coupled hydrodynamic and aerodynamic predictive performance. Limitations of both FAST and the data gathered from the tests arediscussed.