Travel to the U.S. from Visa Waiver Program countries
Effective March 15, 2010, citizens from countries participating in the US Visa Waiver Program who wish to travel by air to the United States must
obtain prior approval through the Electronic
System for Travel Authorization (ESTA). ESTA is used by the U.S. government to screen eligible residents of Visa Waiver Program (VWP) countries before they board a plane to the U.S to determine whether or not they pose a law enforcement or security risk.