Dolphin whistles were recorded near San Clemente Island, offshore of Southern California, by four autonomous high-frequency acoustic recording packages (HARPs) deployed in a sea-floor array (dimensions: 2 km × 2 km) centered around the R/P FLIP. This array layout allowed localization of the calling animals using time difference of arrivals (TDOAs) from the same calls simultaneously recorded on the four instruments. Whistle TDOAs were calculated using cross-correlations of spectrograms. A matched-field least-squares minimization procedure used whistle TDOAs to localize the animals. Successive localizations were combined to track movement over time, revealing local movements of presumably common dolphins (Delphinus spp.), typically during elevated nocturnal activity. These tracks, coupled with the animals’ acoustic activity, provide insight into their behavior and could potentially be used to study their response to various stimuli including anthropogenic sources such as sonar. [This research is supported by CNO-N45.]