Your answer depends on the season during which you're sending your letter and the Antarctic destination for it.
There are periods when there is no postal service to any research station on the continent -- usually about February to about October. On the Antarctic Peninsula, the no-service period may be about April to about August.
It will take a week or ten days.
a week to ten days
About five to seven days.
About 14 days. I've done it.
Your answer depends on where you want to go in Antarctica.
1 to 14 days or more
edyte6
Depends on where you leave from.
I doubt that any helicopter can fly from Antarctica to Australia.
10 to 14 days. Occasionally a week if you are lucky.
It matters whers where you live
5 days