In order to enter Australia, US passport holders will need a valid Australian visa. There are several types of visitor visas to consider, depending on how long you want to stay.

Granted electronically and applied for before your trip, the Australian ETA (Electronic Travel Authority) is among the most popular Australian visa options. It allows you to visit Australia multiple times (as many as you want) within a 12-month period, and for each visit, you can stay for up to 90 days. The 12-month Australia ETA starts from the date it’s granted, with the three-month visitation period beginning when you arrive in the country.

On the Visitor Visa or Tourist Stream visa (also known as Subclass 600), you can visit Australia for up to 12 months. Unlike the ETA, you can only apply for this type of Australian tourist visa when you’re already in the country. This makes it a good candidate for visa extension (see below for further information).

As a business traveler, you can visit Australia on an Electronic Travel Authority visa for general business purposes, like making inquiries, attending conferences, or negotiating contracts. As a business traveler using a valid ETA, you can make multiple visits to Australia in a year, for up to three months (90 days) at a time per visit.

For other business purposes, the Australian government has other visas of differing durations and eligibility requirements. Some offer permanent residency for business owners, while others can be valid for up to five years.

The Australian government’s immigration policies are very strict, so it’s important to take them seriously and abide by your visa term limits. Overstaying your visa can come with unpleasant consequences, like fines, being detained, or deportation. So you want to avoid being “unlawful” and letting your visa expire during your stay.

Once your visa expires, you have a 28-day grace period in which to either leave or find a solution with Australian immigration authorities. After 28 days, you can be deported from the country and banned from re-entry for at least three years.

If you want to stay in Australia longer, check the conditions and terms of your current visa. If your current visa can’t be extended, you’ll either need to leave the country or apply for a new visa.

It’s not possible to extend the Australian ETA during your stay. If you want to extend your trip, you’ll need to apply for a different visa type, like the subclass 600 Visitor Visa Tourist Stream (Apply in Australia).

While it’s possible for some visa types to either extend or apply for a different visa, you shouldn’t wait for your current visa to expire before applying. Check your Australian visa requirements and start the application process for the new visa at least a month in advance.