What documents will be required?
Enforced compliance of the Electronic System for Travel Authorization (ESTA) requirement for VWP travelers is in place. Therefore, VWP travelers who have not obtained approval through ESTA should expect to be denied boarding on any air carrier bound for the United States.
A valid ESTA approval is required for all Visa Waiver Program (VWP) to travel to the United States. The Department of Homeland Security, Electronic System for Travel Authorization (ESTA) is a free, automated system used to determine the eligibility of visitors to travel to the United States under the VWP. It collects the same information as the paper I-94W form that VWP travelers fill out en route to the United States. ESTA applications may be submitted at any time prior to travel. An ESTA authorization generally will be valid for up to two years. Authorizations will be valid for multiple entries into the United States. DHS recommends that travelers submit an ESTA application as soon as they begin making travel plans.