Each year, humpback whales (Megaptera novaeangliae) undertake seasonally predictable, long-distance migrations between high-latitude feeding areas and tropical breeding grounds. However, changes in migration timing have been reported across multiple populations worldwide, raising concerns about the influence of increasing environmental variability and intensifying coastal activity on migration timing and habitat use. Along Australia’s east coast, the eastern Australian (E1) subpopulation has been well studied in several regions, yet fine-scale information on humpback whale occurrence remains limited along the south coast of New South Wales (NSW). Passive acoustic monitoring (PAM) was used to examine humpback whale occurrence in Batemans Bay, NSW, between May and September 2024. A total of 102,960 minutes of acoustic data were analysed, with humpback whale vocalisations detected in 70% of monitored hours and across 87% of monitored days. Detections began on 19 May and were followed by sustained daily occurrence from late May through to the end of the monitoring period in late September. Temporal trends showed a rapid increase in detections from late May, with peak occurrence in early August and a secondary peak in late September. Clear diel variation was also observed, with higher detection rates during low-light periods (dawn, dusk, and night) compared to daytime hours. These results provide the first continuous, acoustically derived description of humpback whale occurrence in Batemans Bay and offer updated insight into migration timing along the NSW south coast. This study demonstrates the effectiveness of PAM for quantifying temporal patterns in humpback whale presence and supports its application for monitoring migratory species in coastal regions subject to increasing anthropogenic pressure.