Information Regarding Visas and Letters of Invitation

In general, citizens of foreign countries seeking to enter the United States must first obtain a U.S. Visa. Some international travelers may be eligible to travel to the United States without a visa if they meet the requirements for visa-free travel such as the Visa Waiver Program.

International participants are strongly encouraged to check their visa status as soon as possible, and if a visa is needed apply for a visa at least 4 months before travel as the VISA process may take 3-6 months. An interview may be required at a U.S. embassy or consulate as part of the visa application process.

For information on visas please see the U.S. Department of State VISA web site The site has a VISA WIZARD and other resources to help determine the type and process for acquiring a VISA. In general travel to conferences is considered under the Business VISA category.

Some important notes:

Be sure you have a valid passport and that your travel will be completed at least six months before the passport expiration date.

There are a number of requirements for travel on the Visa Waiver Program please check the requirements carefully including: Visa applicants may want to include the following with their visa application background materials:
  • copy of the Symposium announcement;
  • copy of the Symposium registration;
  • letter of invitation.

Official Letter of Invitation

Those in need of official letters of invitation from the U.S. Government local host should send a request with the following information to C. Taylor Armstrong

  1. name (as it appears on passport)
  2. date of birth (MM/DD/YYYY)
  3. nationality
  4. passport number
  5. city of visa interview (if available)
  6. role in Symposium (registered participant or registered presenter)

Contact for Official Letter of Invitation:

[This Contact and Organization should be also used for your on-line Visa applications]

Christen Armstrong
National Oceanic and Atmospheric Administration
1315 East West Highway (SSMC3 10340)
Silver Spring, Maryland, USA 20910
Phone: +1-301-734-1033

If you do not receive a confirmation email from Christen Armstrong within the first 3 days after sending your request for Official Letter of Invitation, please contact Alexey Khoruzhiy from PICES Secretariat

Other resources:
The National Academies Web site has additional information about visa-related issues and travel information for travelers to scientific meetings.