Esacus giganteus is widespread around coasts from the Andaman Islands, India, Mergui Archipelago, Myanmar, islands off peninsular Thailand, and Peninsular Malaysia through Indonesia, Brunei, the Philippines, Papua New Guinea, the Solomon Islands, Vanuatu, New Caledonia (to France) and Australia. Its population in Australia may number c.5,000 birds and is probably stable (Garnett and Crowley 2000). Its density in Australia may have decreased locally on islands and in areas of the mainland where there are high levels of human disturbance and coastal development, especially around inhabited islands of the Great Barrier Reef and Torres Strait, and the wet tropical coast (A. Freeman in litt. 2007). Despite this, between the 1920s and 1970s the eastern part of the species's range appears to have extended south into New South Wales (Garnett and Crowley 2000). It is very rare on and around Sumatra, Vanuatu and New Caledonia, where it has not been seen for six years (N. Barre in litt. 2003).