In order to re-enter the U.S. after a temporary absence (not exceeding 5 months) you must carry the following documents:
To travel outside of the country and re-enter the U.S. as an F-1/J-1 student, you must have a valid I-20/DS-2019 which has been endorsed by an International Student Advisor (F-1) or Program Sponsor (J-1). F-1 students may need a new I-20 if they have failed to maintain status.
To facilitate entry into Canada or Mexico as a visitor, you must carry all the documents listed above except for a valid F-1/J-1 Visa stamps for some students. In addition, a visitor's Visa may be required depending on your country of citizenship
Visitor's Visa to Canada and Mexico
F-1/J-1 students or their dependents that are planning a trip to Canada or Mexico should contact the respective consulate offices to determine whether a visitor's Visa to the country is needed prior to your trip.
Mexican Consulate www.sre.gob.mx/acerca/directorio/consulados/seattle.htm
Canadian Consulate www.dfait-maeci.gc.ca
Re-entering the U.S. from Canada on an Expired F-1/J-1 Visa
Most students may travel to Canada, Mexico and Adjacent Islands and re-enter the U.S. on an expired F-1/J-1 Visa if the trip does not exceed 30 days (this is referred to as Automatic Visa Revalidation). Please note, however, that Automatic Revalidation, or entry on an expired visa, does not apply when a student applies for a new F-1/J-1 Visa and is denied in Canada or Mexico.
Retaining Your Original I-94 Card for Re-entry
It is vitally important for students to retain the original copy of their I-94 card when traveling to Canada, Mexico and Adjacent Islands, if they plan to re-enter with an expired Visa under the Automatic Visa Re-Validation law. They will need this document as a substitute for a valid Visa when re-entering the US. Subsequently, when departing the US, students should not relinquish this card to the airlines or an immigration officer.
Under Special Registration (NSEERS: National Security Entry-Exit Registration System), non-immigrant’s from certain countries are required to:
Male citizens or nationals of the following countries are required to comply with the Special Registration (as of December, 2003).
Afghanistan, Algeria, Bahrain, Bangladesh, Egypt, Eritrea, Indonesia, Iran, Iraq, Jordan, Kuwait, Lebanon, Libya, Morocco, North Korea, Oman, Pakistan, Qatar, Saudi Arabia, Somalia, Sudan, Syria, Tunisia, United Arab Emirates, Yemen