Understanding fish movements in relation to areas of contaminated sediment is important for management and remediation. In this study, the movements of white croaker in the Los Angeles and Long Beach Harbors were studied using both active and passive acoustic telemetry tracking. Daily area use for 20 actively tracked fish averaged 94,720 ± 78,720 m2 (± SD), with activity spaces tending to shift from day to day. Long-term dispersal of 93 passively tracked white croaker followed significantly non-random patterns. Fifty-five (59.1%) of passively tracked fish were detected making interregional harbor movements, and these transitions took an average of 4.7 ± 4.1 weeks to complete. Dispersal was significantly faster than what was predicted by an individual-based random walk model generated from short-term white croaker movements recorded during active tracking within the harbor. Longer-term dispersal is likely the result of intentional emigrations rather than daily shifts in activity spaces.