Irrawaddy dolphins are discontinuously distributed mostly in the coastal, shallow, brackish, or fresh turbid waters at the mouths of rivers in southeastern Asia. On the Asian mainland they range from Vishakhapatnam, Andhra Pradesh, India, around the Bay of Bengal to the Strait of Malacca and the Gulf of Thailand. There are freshwater populations in the tributaries at the mouths of the Ganges, in the Irrawaddy as far as 2,300km upstream to Bhamo, and in the Mekong and Sekong Rivers as well as in the Ayeyarwady River