The Visa Waiver Program (VWP) allows eligible nationals of 35 countries to travel without a visa for tourist and business travel of 90 days or less provided they possess an e-passport and an approved authorization through the Electronic System for Travel Authorization (ESTA). As of January 12, 2009, all VWP travelers are required to obtain an authorization via ESTA before traveling to the United States.
The 35 participating countries are: Andorra, Australia, Austria, Belgium, Brunei, Czech Republic, Denmark, Estonia, Finland, France, Germany, Hungary,
Iceland, Ireland, Italy, Japan, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Monaco, the Netherlands, New Zealand, Norway, Portugal, San Marino, Singapore, Slovakia, Slovenia, South Korea, Spain, Sweden, Switzerland, and the United Kingdom.
Canada, Mexico, and Bermuda are not participants in the Visa Waiver Program. The Immigration and Nationality Act includes other provisions for visa-free travel for nationals of Canada and Bermuda under certain circumstances. See Who from Canada, Mexico and Bermuda, Needs a Nonimmigrant Visa to Enter the United States Temporarily on the U.S. Department of State website.
Travelers arriving to the U.S. under the VWP are admitted either as WT (Waived Tourists) or WB (Waived Business). Regulations are equivalent to those governing B-1(Business) and B-2 (Tourist) visas except that, unlike a B-1 and B-2, those in WB or WT status are not permitted to remain in the U.S. for more than 90 days with (NO EXTENSIONS) and are not eligible to change their status.
Certain travelers still need to apply for a visa, such as those who plan to work or study, stay more than 90 days, or who might otherwise be ineligible for a visa. Travelers previously denied visas, or who have criminal records, or who believe they may be ineligible for a visa should contact the nearest U.S. embassy or consulate before attempting to travel on the VWP.