We spent 5 weeks in Australia this fall. We never used US currency, nor did we ever see anyone else use it. I don't think it's accepted there. We used our American Express card when we could because it had a lower surcharge, 2%, then our MasterCard and Visa, 3%. But at least the credit cards gave us a better exchange rate than we could have gotten from a currency exchange or bank with travelers checks or cash. For our cash expenses, we used the ATMs to withdraw Australian dollars from our US bank account. Again, the exchange rate was pretty good, but we had to pay several dollars in ATM fees everytime we got cash. So it's a good idea to budget for as few withdrawals as possible. The exchange rate we could have gotten in the US before leaving was terrible.