The average head and body length of P. giganteus is 170-406 mm. Forearm length is 85-228 mm and wingspan ranges from 610-1,700 mm. Male Pteropus giganteus weights range between 1,300 and 1,600 grams while females average 900 grams.

They prefer forests or swamps, along coastal areas of islands. They roost in colonies by day, and may use the same roosting site for years.

A large body of water nearby is necessary for survival. At night, the bats fly to neighboring fruit trees to feed. They mainly drink the juice of the fruit, spitting out the pulp and seeds. They may also drink sea water for the minerals.

In the summer the bats form colonies or "camps" and young are born shortly thereafter. They remain with the females for 3-4 months. Mating takes place in these camps, but the sexes separate afterward.

Pteropus giganteus is found in the Maldive Isls, India (incl. Andaman Isls), Sri Lanka, Pakistan, Bangladesh, Nepal, Burma, Tsinghai (China). (The Tsinghai record requires confirmation. Cambodian records are apparently erroneous).