This chapter presents the main geophysical applications of HFR, based on the main principles developed throughout this book. The most successful and specific application of HFR is the near real-time measurement of hourly surface currents in coastal areas, based on the measurement of radial currents from the shift of the first-order Bragg peaks. Another standard product today is the estimation of ocean wave spectra and global ocean wave parameters. As this involves the second-order Doppler spectra and complex inversion procedures, it is less accurate and more challenging than surface current measurements, and has less spatial coverage than the latter. The last two by-products of HFR are the surface wind vectors and the possible detection of tsunamis, which we will briefly review.