What is an ESTA?

An ESTA (Electronic System for Travel Authorization) is a travel authorization for visa-free travel to the United States for either business, tourism, or transit. It is valid for multiple stays of up to 90 days and expires after 2 years or until your passport expires (whichever comes first).
While most authorizations are granted soon after the application has been submitted, it is recommended that travelers apply at least 72 hours prior to departure. The authorization is tied to your passport number, so you are not required to bring a printout or copy.

Who require an ESTA?

All those entering the United States by air or sea through the Visa Waiver Program require an ESTA. This requirement extends to non-ticketed children. Those only transiting the United States en route to their final destination also require an ESTA.

Which countries are part of the Visa Waiver Program?

Andorra, Australia, Austria, Belgium, Brunei, Chile, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Japan, Latvia, Liechtenstein, Lithuania, Luxembourg, Monaco, Netherlands, New Zealand, Norway, Portugal, Republic of Malta, San Marino, Singapore, Slovakia, Slovenia, South Korea, Spain, Sweden, Switzerland, Taiwan and United Kingdom