Irrawaddy dolphins are distributed in tropical/subtropical waters from the east coast of India, east through Bangladesh, Myanmar, Thailand, Cambodia and Vietnam to Malamapaya Sound, Philippines and south through Malaysia, Indonesia and Papua New Guinea to northern Australia.

Although Irrawaddy dolphins have a wide distribution, the species will soon be separated into two distinct subspecies: one occurring in Australia/Papua New Guinea and the other in Asia. Conservation of Asian populations is therefore essential – as well as continued efforts in Australia.

Riverine populations are found in only three rivers throughout the world: The Ayeyarawaddy River (Myanmar), Mahakam River (Indonesia) and the Mekong River (Lao, Cambodia and Vietnam) – already mentioned previously. Due to pressures from human competition for freshwater resources, all riverine populations are thought to be under severe threat of extinction.