Electronic System for Travel Authorization (ESTA)
On January 12, 2009, the Electronic System for Travel Authorization (ESTA) became mandatory by the Department of Homeland Security (DHS). This online system is part of the Visa Waiver Program (VWP), and all nationals or citizens of VWP countries who plan to travel to the United States for 90 days or less. Qualified VWP applicants traveling to the United States for business or for pleasure need to receive an electronic travel authorization prior to boarding a U.S.-bound airplane or cruise ship.
Effective January 20, 2010, the U.S. Department of Homeland Security initiated a transition to enforced ESTA compliance, and VWP travelers who have not obtained approval through ESTA should expect to be denied boarding on any air carrier bound for the United States.
Note: ESTA is not required for Canadian citizens, and ESTA is not needed for entry into the United States via the land border.