Two world's largest Indo-Pacific humpback dolphin (Sousa chinensis) populations are both in Guangdong province, China, but its suitable habitat there has not been evaluated. We used MaxEnt to predict the suitable habitat of humpback dolphins in Guangdong based on environmental variables and sighting data. A total of 5,545.9 km(2) of suitable habitat (probability >= 0.5) was estimated to be available for humpback dolphins, mainly occurring in waters of the Pearl River estuary (the Pearl River Estuary and west, Hengqin Island-Chuanshan Islands-Mausoleum Island, approximately 3,637.6 km(2)), waters near Zhanjiang (Leizhou Bay, Zhanjiang Port, and Jianjiang Estuary, approximately 1,852.7 km(2)), and those near Chaozhou-Shantou (waters near Guarig'ao Bay and Nan'ao Island, approximately 55.6 km(2)). Currently, only 8.89% of the suitable habitat for Indo-Pacific humpback dolphins is under protection. Therefore, we propose extending the range of current nature reserves and establishing new nature reserves in the suitable habitat area.