Making sure you have the right visa can be one of the biggest hassles of travelling abroad. In the last of our series of bitesized guides to some of the more complicated travel regulations, we talk you through the Western Hemisphere Travel Initiative (WHTI).

What is it?

The Western Hemisphere Travel Initiative (WHTI) requires all citizens of the United States, Canada, Mexico, and Bermuda to have a passport or other accepted document that establishes the bearer's identity and nationality to enter or depart the United States from within the Western Hemisphere.

The travel document requirements make up the departments of State and Homeland Security's Western Hemisphere Travel Initiative. This change in travel document requirements is the result of recommendations made by the 9/11 Commission, which Congress subsequently passed into law in the Intelligence Reform and Terrorism Prevention Act of 2004.

The air travel requirements were brought into effect in 2007, requiring all travellers to present a passport upon entering the United States. Land and Sea requirements are currently being implemented and all travellers will require the correct documentation when entering ports from 1 June 2009.

Who is it for?

Residents of Canada, Mexico, Bermuda and United States.

WHTI-compliant documents include:

• US or Canadian passports;
• Trusted Traveler Card (NEXUS, SENTRI, or FAST);
• US Passport Card;
• State- or province-issued Enhanced Driver's Licenses (when and where available);
• Form I-872 American Indian Card, or (when available) enhanced tribal cards;
• Military identification cards presented by members of the U.S. armed forces travelling on official orders.
• US Merchant Mariner Document (for U.S. citizens, when conducting official maritime business).

US Permanent Residents:

Lawful permanent residents of the United States should present acceptable evidence of their lawful residence status when entering the country, such as a Permanent Resident Card (I-551).

How much?

There is no cost involved in the WHTI initiative itself, however, varying costs may apply for those needing to apply for a valid passport or other relevant documentation.

How to apply?

Travellers do not need to apply in advance, but must ensure that they have the correct documentation upon arrival in the United States as stated above.

See the rest of our bitesized guides to passport and visas:
Schengen Visas

Visa and passport information is updated regularly and is correct at the time of publishing. You should verify critical travel information independently with the relevant embassy before you travel.