Humpback whales (Megaptera novaeangliae) undertake one of the longest migrations in the animal kingdom. Stored energy is crucial for a successful migration, despite this few studies have investigated the relationship between migration timing and body condition (BC). Using unmanned aerial vehicles, we quantified the BC of east Australian humpback whales. We collected data on 515 individual whales (49 calves, 166 juveniles, 251 adults, and 49 lactating females) during their northbound and southbound migrations between June and October 2020. For adults and juveniles, we explored the loss of BC between migration direction (north/south) and the relationship of migration timing (day of year) and BC. We found a significant loss in BC between migration direction for adults (9.8%) and juveniles (18.3%). However, migration timing did not influence BC for either reproductive class. Cow/calf pairs were analysed using relative calf length (percentage of mother’s length) as a proxy for time. Migration timing and BC was found to be significant for calves, however not significant for lactating females. The lack of a correlation found for adults and juveniles suggests that BC is not the main driver of migration time. However, calf BC may be a significant factor for the migration timing of cow/calf pairs.