Current gov.au travel advice re: USofA: https://www.smartraveller.gov.au/destinations/americas/unite...

  Updated:16 April 2025

  Entry requirements are strict. US authorities have broad powers to decide if you're eligible to enter and may determine that you are inadmissible for any reason under US law.
  Check US entry, registration, transit and exit requirements.
  Whether you're travelling on a visa or under the Visa Waiver Program, ensure you understand all relevant terms and conditions before attempting to enter the United States.

  Every country or territory decides who can enter or leave through its borders. For specific information about the evidence you'll need to enter a foreign destination, check with the nearest embassy, consulate or immigration department of the destination you're entering. 

  Australian citizens can now apply for the Global Entry program direct through US Customs and Border Protection (USCBP). The Global Entry program is a US Government program that allows faster border clearance entering the United States for some Australians subject to strict eligibility criteria.

  If you're visiting the United States for less than 90 days, you may be eligible to:
    apply for an Electronic System for Travel Authorization (ESTA) and
    then enter under the Visa Waiver Program (VWP)
  Otherwise, you'll need to get a visa before you travel.