The Indo-Australian Plate
By the name, you can probably identify that it contains parts of India and Australia. But as with most tectonic plate boundaries, they often consist of both continent and ocean crust.
Continental drift means that plates are never idle. Over time, they move at a snails pace. For example, the Indo-Australian Plate moves at an average rate of about 3 centimeters per year.
Two plates separated but we often count them as one
The Indo-Australia plate is a major plate combining the Australian and Indian Plate. But they are widely considered to be two separate plates.
The Indo-Australia plate stretches from Australia to India. It also includes the oceanic crust from the Indian Ocean. The north-east side of the Australian plate converges with the Pacific Plate.
Long ago, Australia, India and Antarctica were once connected as the supercontinent Gondwana. As part of the supercontinental cycle, India drifted apart moving northwards.
At about 58,900,000 km2, the Indo-Australia plate is the sixth largest plate tectonic boundary.