A 9.0-magnitude undersea earthquake occurred near the coast of Japan on March 11, 2011, and generated a powerful tsunami, which propagated across the Pacific Ocean. The high-frequency (HF) surface wave radar is an operational tool for coastal monitoring worldwide. The oceanographic WERA HF radar located in Chile was in operation and provided measurements in real-time when the tsunami waves reached this region. For the first time impressive tsunami signatures of changing sea surface current velocities were observed by the HF radar system. The tsunami wave train can be clearly seen in the radar measurements. It was found to be significantly correlated with the water level measurements by tide gauges. © 2011 DGON.