Are the food 52 contests available for Australians?

The rules (https://food52.com/contests/about) say nothing about having to be from any specific country, so I bet you could enter.

Yes, you certainly can! The only caveat is that occasionally we offer physical prizes to the winners, and we typically can't ship those overseas. But if you have someone who can receive them for you in the U.S., there shouldn't be any issue.