Visa Waiver Program

Starting January 12, 2009, have an approved Electronic Travel Authorization (ESTA). ESTA is an automated system that determines the eligibility of visitors to travel to the United States under the Visa Waiver Program (VWP); note that multiple ESTA applications can be submitted at the same time for persons traveling in groups.

You may use VWP if you meet the following criteria:

Plan to travel to the U.S. for 90 days or less;
Are traveling for tourism or business;
Carry a machine-readable passportwhich, in most cases, must be valid for at least six months after your expected departure from the U.S.;
Have a return ticket or onward ticket to most non U.S. destinations;

You WILL need a visa, and may not use VWP, if any of these criteria apply to you:

If you are a nationals of VWP countries who have traveled to or been present in Iraq, Syria, Iran, Sudan, Libya, Somalia, or Yemen at any time on or after March 1, 2011 (with limited exceptions); or you are a nationals of VWP countries who are also nationals of Iraq, Syria, Iran, or Sudan.
Want to remain in the United States for longer than 90 days;
Intend to travel by private/charter aircraft or sea carriers;
Want to work or study in the United States. For more on the appropriate visa classifications, please see state.gov;
Have been deported or refused admission to the U.S. before, or failed to comply with a previous VWP admission or visa. This includes overstaying a previous admission by even one day.
Have a criminal record;