In Australia,
Dendrelaphis calligaster are found on the eastern side of the
Cape York Peninsula (Queensland) as far south as
Mackay. On the western side, their range is poorly mapped. They also occur on many of the
Torres Strait Islands. On the New Guinea mainland, they are widespread at elevations below in both Indonesian and Papua New Guinean parts of the island. They occur also on many nearby islands. The
Reptile Database also lists this species from the Solomons.
Dendrelaphis calligaster is primarily
arboreal but can also forage on the ground. It can be found in rainforest, mangroves, dense secondary regrowth, and tropical woodlands. It is abundant throughout its range. ==Behaviour and ecology==