It is endemic to the island of Borneo and known from Sabah and Sarawak, Malaysia,[1][4] and from Brunei.

The fingers are slender and have weakly developed terminal discs and rudimentary webbing.

The toes are webbed and have small rounded disks at their tips.

[3] Adult Ansonia platysoma occur on the floor of montane forests at elevations between 600 and 1,600 m (2,000 and 5,200 ft) above sea level.

It does not appear to adapt to habitat modification, but the known populations are within well-protected areas: the Crocker Range and Kinabalu National Parks in Sabah, and the Gunung Mulu National Park in Sarawak.