Why is Australia geographically isolated from other continents?

Australia’s geographic isolation is primarily the result of long-term geologic history and plate tectonics.

For hundreds of millions of years, Australia was a component of the supercontinent Gondwanaland. Beginning in the Mesozoic Era, the continent began to break away from its neighbors due to seafloor spreading. Specifically, rifting between Australia and Antarctica initiated in the Late Jurassic, eventually leading to their complete separation and the creation of oceanic margins on all sides of the Australian landmass.12

Additionally, back-arc spreading in the Pacific Ocean separated Australia from the Lord Howe Rise and New Zealand. Since these separations, Australia has drifted northward, further distancing itself from its former Gondwanaland connections. This prolonged physical detachment is the fundamental reason for the continent's global isolation, which has profoundly influenced the evolution of its unique flora and fauna.12