Helical, cross‐flow turbines have a number of attractive properties for use in generating electricity from fast moving tidal, ocean, and river currents. These include low torque oscillations, inherent flow alignment in a vertical orientation, and a convenient form factor. However, the hydrodynamics of these turbines are not as well understood as for axial flow or straight‐bladed, cross‐flow variants. This paper presents results from simulations, laboratory experiments, and field studies of helical, cross‐flow turbines with emphasis on performance, wake characteristics, and responsiveness to inflow turbulence. These results demonstrate the utility of combining numerical modeling with laboratory and field experiments and suggest a number of avenues for future study.