Marine and hydrokinetic (MHK) technology performance testing in the laboratory and field supports the US Department of Energy’s MHK program goals to advance the technology readiness levels of MHK machines, to ensure environmentally responsible designs, to identify key cost drivers, and to reduce the cost of energy of MHK technologies. Laboratory testing results from scaled model machine testing at the University of Minnesota’s St. Anthony Falls Laboratory (SAFL) main channel flume are presented, including simultaneous machine power and inflow measurements for a 1:10 scale three-bladed axial flow turbine used to assess machine performance in turbulent flows, and detailed measurements of inflow and wake flow velocity and turbulence, including the assessment of the effects of large energetic organized vortex shedding on machine performance and wake turbulence downstream. Scaled laboratory testing provides accurate data sets for near- and far-field hydrodynamic models, and useful information on technology and environmental readiness levels before full-scale testing and demonstration in open water. This study validated turbine performance for a technology in order to advance its technology readiness level. Synchronized ADV measurements to calculate spatio-temporal characteristics of turbulence supported model development of the inflow turbulence model, Hydro-TurbSim. Wake flow measurements supported model development of the far-field model, SNL-EFDC to optimize spacing for MHK machine arrays.