Be sure the visa in your passport (1) will still be valid on the date you plan to re-enter the U.S., and (2) still has entries remaining (either has an “M” for unlimited multiple entries or at least “1” entry left). If you must renew your visa while out of the U.S., see the information below on reweing a visa. If you are traveling to Canada, Mexico, or a country in the Caribbean and your visa has expired, please also read the information below on Automatic Visa Revalidation.
What documents do I need to renew my visa?
It depends on your immigration status; see below for what ISSS recommends. Check the website of the U.S. consulate  you will visit to see exactly what documents, including forms and photos and fees, you will need to present. You will need to fill out application forms, which may be downloaded from the Department of State  website.
J-1 scholars and dependents should take:
How long will it take to get a new U.S. visa?
It depends on your situation. Students and scholars are advised to go to the consulate to renew their visas at the earliest possible opportunity to avoid possible delays. Do not wait until the end of your stay abroad. If you know you will be required to appear in person at the consulate, try to make an appointment with the consulate even before you leave the U.S. Many embassies have web sites with information about their visa application procedures. View a listing of U.S. embassies and consulates.
Individuals in J status can re-enter the U.S. from Canada, Mexico, or the Caribbean Islands* on an expired visa if:
NOTE: The automatic revalidation option is NOT available to:
(1) Nationals of a country designated as a State Sponsor of Terrorism . You would be required to obtain a new U.S. visa before being allowed to re-enter the U.S., and in all probability could only get a new visa from the U.S. consulate in your home country or the consulate that services your home country
(2) Canadian “landed immigrants” who have never had an F or J visa. You would be required to obtain a U.S. visa before being allowed to re-enter the U.S. You may be able to obtain the visa from a U.S. consulate in Canada, unless you are a citizen of one of the seven countries listed above or one of the countries likely to be subject to the Security Advisory Opinion.
For more information visit the Department of State  website.
*The Code of Federal Regulations at 8 CFR 286.1(a) defines "adjacent islands" to include Anguilla, Antigua, Aruba, Bahamas, Barbados, Barbuda, Bermuda, Bonaire, British Virgin Islands, Cayman Islands, Curacao, Dominica, the Dominican Republic, Grenada, Guadeloupe, Haiti, Jamaica, Marie-Galante, Martinique, Miquelon, Montserrat, Saba, Saint Barthelemy, Saint Christopher, Saint Eustatius, Saint Kitts-Nevis, Saint Lucia, Saint Maarten, Saint Martin, Saint Pierre, Saint Vincent and Grenadines, Trinidad and Tobago, Turks and Caicos Islands, and other British, French and Netherlands territory or possessions bordering on the Caribbean Sea. Note that Cuba is NOT considered an adjacent island for the purpose of travel into the United States.
“Third-country national” means that you are not a citizen of the country in which the U.S. consulate where you will attempt to renew your visa is located. For example, citizens of China who try to renew their visas in Mexico are “third country nationals.”
In general, it has become riskier to try to renew your visa in a country that is not your own. The United States Department of State says, “Individuals seeking appointments should be aware that applicants may be more likely to encounter difficulties at the time of interview when they apply for a visa outside of their home district. Consular officers...will deny visas whenever they believe there are fraud indicators present, or their lack of knowledge of local conditions and familiarity with documents in the applicant's home country prevents them from properly adjudicating the case.” This means that you could attempt to renew your visa in a country that is not your own, be denied, and then be unable to re-enter the U.S. until you travel directly to your home country and get a new visa there.
Getting a U.S. Visa in Canada or Mexico
If you plan to get a U.S. visa at a consulate in Canada or Mexico, you must make an advance appointment with the U.S. consulate you plan to visit. Please note that only individuals who meet specific requirements will be allowed to do this if Canada or Mexico is not your country of citizenship. If your visa is expired and you apply for and are denied a new visa in Canada or Mexico, you cannot re-enter the U.S. under the terms of automatic revalidation. Instead you will be required to return directly to your home country to apply for a new visa in the U.S. consulate there.
Be sure you have any visas needed to enter countries other than your own that you plan to visit. Go to the website of the country you would like to visit  to see if you might need a visa to enter the country to which you are traveling.
Some visa applicants may be subject to additional screening. These security checks are performed by the U.S. Department of State, and can take several weeks or months to complete. There are at least three ways a scholar can be subject to a security check: (1) country of citizenship: generally for citizens of Middle Eastern or predominantly Islamic countries, although citizens of any country can be subject; or (2) the area of study/research is highly technical or viewed as “sensitive:” citizens of any country (particularly those listed above as well as China and India) have been selected for security checks for this reason. The “Sensitive Majors” list includes most engineering disciplines, chemical and biochemical/biomedical sciences, computer science, genetics, certain branches of physics, nuclear and laser technologies, actuarial science, and even urban planning! Finally, people can be subject to a security check if (3) a preliminary check at the consulate reveals potential criminal history or other “security concerns.”
When a security check occurs, there is absolutely nothing ISSS, the University of Iowa, or any political liaison can do to speed up the process. We strongly suggest that you contact ISSS so that we may assess your situation BEFORE making travel plans.
Representatives from the U.S. Department of State have suggested that students and scholars who believe they could be subject to a security advisory opinion based on the “sensitive” areas of study/research should take a letter from their employing department that briefly describes – in very elementary language – the type of research you are doing or the focus of your studies. The point is to try to illustrate that your work is not a “threat” to U.S. national security. It is still possible you may be subject to the security clearance, but this letter could help speed things up.
How Likely Is It That My Visa Application will be denied?
There are never any guarantees that a visa will be renewed. However, in general it is unlikely that a visa will be denied to a scholar who is in the midst of a program. But as noted above, delays may be more likely to occur.
What If My Application for a New Visa Is Denied?
Ask the consular officer to give you a written explanation for the denial. Contact ISSS immediately and supply details about your visa interview, what you were asked and what you replied. Give us the date and place of the denial and, if possible, the name of the consular officer who issued it. If you have any reason to think your situation might place your visa application in unusual jeopardy, you may want to discuss it with an ISSS adviser before traveling (and preferably before purchasing tickets). Please note ISSS cannot reverse denial decisions.
While you are still at the Port of Entry, make sure the information on your I-94 is CORRECT (for example, that it is marked as “D/S” for Duration of Status rather than given a specific end date, and that the appropriate category – J-1 – is marked on it. If it is not, bring it to the attention of the officer at the Port of Entry. It will be much more difficult and time-consuming to attempt to get it corrected later. You should also certainly keep a photocopy of your new visa and I-94 (front and back) in a safe place.