Black pythons have large head plates and heavily pitted lips.
Adults are black. The faces have pale yellow bars on the labial scales and the necks and anterior bodies of black pythons are patterned with yellow or ivory diagonal lateral bars with incomplete yellow rings across the top of the neck and anterior body. Some older specimens from Papua-New Guinea are almost patternless solid black. This is a highly iridescent species. 8'-13', with eastern populations distinctly larger than western populations.