Sites of high tidal current power potential are mostly found at narrow tidal passages or channels. Not many coastal sites with unbounded ocean with high tidal current speed have been reported. The coastal sea near the Cape Fuguei in northwestern Taiwan is such a site with a high tidal power potential. The purpose of this study is to investigate the tidal current speed at this location for assessing the tidal current power potential. In-situ and remote sensing instruments were deployed simultaneously to measure the temporal and spatial distributions of tidal currents. An Acoustic Doppler Current Profiler (ADCP) was deployed at a 26 m depth site and an X-band marine radar was installed at a coastal building. Two measurements lasting over one month were done. Both instruments showed the maximum current speed at the surface was more than 3.5 m/s in the measurement period. ADCP measurements showed that the time mean speed in the upper layer (−1.7 to −6 m) was 1.5 m/s. The current speed decreased with depth slightly. It was also found from both ADCP and radar measurements that in the surface layer, the probability of duration for current speed exceeding 1 m/s was more than 70%. In addition, radar measurement showed that the average surface current speed at the area from 2 km offshore out to 4 km (radar offshore limit) was more than 1 m/s. The size of this area is more than 15 km2. Our investigations indicated that this area has a high tidal power potential for current turbine deployments.