What are Antarctica's flags?

Answer 1

There is no 'Antarctic flag', because there is no sovereignty in Antarctica. Some people purport to have designed such a flag, but it's only value is as a collectible in a collectible market. It has no other value.

Answer 2

There are no countries, no sovereignty on the Antarctic continent. This means no flags, no currency, no stamps and so forth for the continent.

Claimant nation-states, however, have produced coordinate-style flags, currencies and stamps, in efforts to exude their claims on Antarctic territory.