Abstract The quality and vertical correlation scales of high-frequency (HF) radar-derived ocean surface current measurements from an ocean surface current radar (OSCR) are assessed by comparing surface to subsurface current observations from 11 June to 8 July 1993 at directional discus buoys DW and DE, each instrumented with a three-axis ultrasonic current meter at the 13.8- and 9.5-m depths, respectively. A dual-station OSCR mapped the current fields at 20-min intervals at a horizontal resolution of 1.2 km over a 30 km × 44 km domain inshore of the Gulf Stream using the HF (25.4 MHz) mode. Over a 27-day experimental period, surface current observations were acquired 97% of the time extending to the maximum theoretical range of 44 km. Linear regression analyses indicated a bias of 2–4 cm s−1 and slopes of O(1). While there were periods when the daily averaged complex correlation coefficients were highly correlated (>0.8), periods of low correlation (<0.3) are explained in terms of vertical phase differenc...