Humpback whales with dependent calves are generally considered to be less social than other adult cohorts. Groups containing more than one calf are rarely seen, however, mother-calf social behaviours are not well studied outside of the breeding grounds. Observations of multiple mother-calf pairs have been reported from Hervey Bay, Queensland; a known resting area on the southern migration route in East Australia. Here, we use long-term photo-identification data to document multiple mother-calf pairs in Hervey Bay, QLD and Eden, NSW. Between 1988 and 2022, we found that 34% of humpback whale groups in Hervey Bay and 44% in Eden contained at least one calf. Of these groups, 8.8% in Hervey Bay and 10.4% in Eden contained two or more calves. Our results also demonstrated an absence of this behaviour in the Great Barrier Reef Marine park; the breeding area for the East Australian humpback whales. We suggest that this affiliative behaviour could serve a social function for developing calves and becomes more prevalent as the calves get older. These results provide important insight into humpback whale social behaviour and maternal strategies and should be incorporated into management plans.