Travel and Visa Information

All international visitors regardless of country of origin must present a passport or secure document when entering the United States.  Most travelers to the United States must hold a valid visa and a passport that is valid six months longer than the intended visit. The purpose of the visit determines what type of visa will be needed. Visitors planning to visit or attend a meeting will most likely apply for a B1/B2 visa. More information on this can be found at the State Department website.

Attendees from Canada and Mexico are reminded to bring a valid passport to cross into the United States. Citizens of 35 countries in Europe and the Far East may visit the U.S. for up to 90 days without a visa if the attendee has a passport with a computer-readable bar code under the Visa Waiver Program (VWP). Details can be found at the U.S. Department of State web site at or contact your local American consulate.

International visitors to the U.S. under the Visa Waiver Program are now required to apply for travel authorization online. To apply visit the Electronic System for Travel Authorization web site at

If you do not already have current ESTA authorization, we recommend that you apply as soon as you know you will be traveling to the United States under the VWP. Effective January 20, 2010, the Department of Homeland Security began enforced compliance of the Electronic System for Travel Authorization (ESTA) requirement for VWP travelers.  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.


Electronic System for Travel Authorization (ESTA) is an automated system used to determine the eligibility of visitors to travel to the United States under the Visa Waiver Program (VWP). ESTA approval authorizes a traveler to board a carrier for travel to the United States under the VWP.

ESTA is not a visa. It does not meet the legal requirements to serve in lieu of a U.S. visa when a visa is required. Travelers that possess a valid U.S. visa may travel to the United States on that visa for the purpose it was issued. Travelers traveling on valid visas are not required to apply for an ESTA. In the same way that a valid visa does not guarantee admission to the United States, an approved ESTA is not a guarantee of admission to the United States.

VWP applicants are required to complete a green Form I-94W and a white Customs declaration upon arrival in the U.S. besides an ESTA authorization.

Approved ESTA applications are valid for a period of two years, and multiple trips to the United States without the traveler having to re-apply for another ESTA. The ESTA travel information may be updated before each trip to the U.S., but it is not required. When traveling to the U.S. with the approved ESTA, you may only stay for up to 90 days at a time - and there should be a reasonable amount of time between visits so that the CBP Officer does not think you are trying to live here. There is no set requirement for how long you must wait between visits.

Travelers whose ESTA applications are approved, but whose passports will expire in less than two years, will receive an ESTA valid until the passport's expiration date.

A new ESTA authorization is required if:

  1. You are issued a new passport,
  2. You change your name (first and/or last)
  3. You change your gender
  4. Your country of citizenship changes
  5. Your circumstances change, e.g., you are convicted of a crime of moral turpitude or you develop a contagious disease. Such a change may require you to get a visa to travel to the U.S. You must re-apply and your application must reflect the change in your circumstances or you may be denied entry upon arrival in the United States.

DHS recommends that you apply for ESTA authorization as soon as you know you will be traveling to the United States under the VWP.

Additional Information on Visas and Other Entry Requirements

Western Hemisphere Travel Initiative
Documentary Requirements for Entry to the United States
U.S. Nonimmigrant Visas
Visa fees and Reciprocity tables

How do I apply for a visa?

As a standard part of the visa process, the State Department is now requiring that consular officers interview almost every applicant. Some consulates may have a long wait for an interview so applicants should contact the consulate to schedule an interview as early as possible. Furthermore, many visa applications are sent to the State Department in Washington, D.C. to be reviewed by several agencies. Because of the number of visa applications and the need for thorough security reviews, the process can take several months. Therefore, it is advisable for travelers to apply for their visas as early as possible. Contact the nearest U.S. consulate or embassy in your country for details on visa application procedures at that post

What should I do once I arrive in the United States?

All travelers arriving in the United States are met by an immigration officer who examines each passport and visa, validates the Arrival-Departure (I-94) card, and determines the length of time the visitor may stay in the United States.  While the visa issued by the consulate allows a visitor to apply for admission to the United States, the final decision is made by the immigration officer. Visitors should be prepared to explain what they will be doing during their visit, where they will stay, and when they plan to return to their country.

U.S.-VISIT biometric procedures apply to all international travelers holding a non-U.S. passport or visa. This also applies to all visitors under the Visa Waiver Program. For further information see the Department of Homeland Security U.S.-VISIT Program web site.

Visa Validity, Single and Multiple-entry Visas, Length of Stay

The visa validity date is the time period during which the applicant must use the visa to enter the United States.  A person with a multiple-entry visa valid for one year can make several trips to the United States during that year.  Some people will be issued single-entry visas only; therefore if they travel outside the United States they must apply for another visa before they return.  The visa validity date has nothing to do with the length of stay which is determined by the immigration official at the port of entry.

Additional Information

Health Insurance: Medical care in the United States can be very expensive. All visitors should carry adequate health insurance valid for the duration of their stay in the United States.

Driving in the United States: Visitors who wish to rent cars must have a major credit card and a valid driver’s license from their own country.  In some cases, an international driver’s license may be required. Contact the car rental company of your choice for specific information.

Documents: Federal law requires that all non-U.S. citizens carry evidence of their lawful status with them at all times. This is especially important for all travel, international or domestic. It is advisable to keep copies of all pages of the passport, visa, I-94 Arrival-Departure card, and supporting documents such as DS-2019 forms, in a safe place in case of loss of the original documents.

Customs information and travel tips: Click here for more information on U.S. customs and border regulations. Click here for tips from the Transportation Security Administration. The U.S. Department of Homeland Security offers additional tips to travelers.

Letters of Invitation

If you need a letter of invitation, please contact the Conference administration. For security reasons, letters of invitation are provided only for registrants who have already registered and paid the appropriate fees.


Disclaimer: While this information is provided for your convenience, the Conference administration makes no guarantees regarding accuracy or completeness, nor shall be liable for the results of any and all uses of this information.

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