To fulfill the passport requirements, you must present a machine readable passport, if you’re traveling to the USA under the Visa Waiver Program (click here to learn more about VWP).
Passports issued on or after October 26, 2006: e-PASSPORTS
Any passport issued on or after this date by a Visa Waiver Program (VWP) country must be an e-Passport for VWP travelers to be eligible to enter the United States without a visa.
What’s an e-passport?
An e-Passport contains an electronic chip. The chip holds the same information that is printed on the data page: the holder’s name, date of birth, and other biographic information. The document also contains a biometric identifier. For more information.
Passports issued October 26, 2005 – October 25, 2006: DIGITAL PHOTOGRAHPS
Older, but still valid passports issued or renewed/extended by Visa Waiver Program countries between October 26, 2005, and October 25, 2006, must include a digital photo printed on the data page, or the traveler will be required to obtain a visa. A digital photo is one that is printed on the page, not a photo that is glued or laminated into the passport.
Passports issued before October 26, 2005: MACHINE-READABLE ZONES
Older, but still valid passports issued by Visa Waiver Program countries before October 26, 2005, must have a machine-readable zone. A machine-readable passport has two lines of text as letters, numbers and chevrons (along with the bearer’s picture.
For more information on the passport requirements.
Beginning January 12, 2009, eligible citizens or nationals from all Visa Waiver Program countries must obtain approval through ESTA prior to traveling to the United States under the Visa Waiver Program.
The Electronic System for Travel Authorization (ESTA) is a new fully automated, electronic system for screening passengers before they begin travel to the United States under the Visa Waiver Program. You are encouraged to do this as soon as you are planning your trip to the USA and no later than 72 hours prior to travel. Click here to submit your application. As of September 8th 2010, there will be a fee of 14 US $* you have to pay when you apply for your ESTA document.
An ESTA approval only authorizes a traveler to board a carrier for travel to the USA under the VWP. An approved ESTA is not a guarantee of admissibility to the USA at a port of entry.
For more information.
Source of information: US Department of Homeland Security.
*Fee accurate at time of publishing