Timber harvesting in eucalyptus plantations poses a significant disturbance to koala populations, yet little is known about how individuals respond behaviorally throughout the harvest process. This study examines the home range size, movement velocity, and dispersal patterns of koalas before, during, and after harvest in Tasmanian blue gum plantations (Eucalyptus globulus) on Kangaroo Island, South Australia, and compares them to a control population on the mainland of South Australia in Belair National Park. Using GPS telemetry data from 51 individuals, considerable variability was found in spatial behavior on plantation land compared to the control in native vegetation in Belair, as well as in post-harvest behavioral responses, shaped by age class and sex. While some koalas remained within their original ranges, others dispersed further, occasionally crossing property boundaries. These results underscore the importance of landscape-scale planning and the retention of movement corridors to support wildlife in production forests. These findings provide insight into koala resilience and habitat use following disturbance, with implications for future plantation management and conservation of arboreal mammals in modified environments.