(Excluding Cuba)
This means that you can re-enter the U.S. with your expired visa stamp.
F and J visa holders who travel to Canada, Mexico, or an adjacent island (other than Cuba) for 30 days or less with an expired visa stamp, may be eligible for an automatic extension of their visa upon reentry to the U.S. The visa will be extended to the date of application for readmission to the U.S. This provision, contained in 22 CFR 41.112(d), does not apply to those whose visas have been canceled or those who do not have a visa stamp.
As of April 1, 2002, travelers from the following countries are not be eligible for automatic extension: Libya, Syria, Iraq, Iran, Sudan, North Korea, and Cuba.
A student or scholar who has an expired visa stamp and who has applied for a visa stamp in Canada, Mexico, or an adjacent island, and been denied, is not eligible for automatic extension. A student who has been visiting, and has not applied for a visa stamp is eligible.
The student or scholar must have maintained valid status, and must intend to continue maintaining valid status.
Those who have changed their visa status in the U.S. are eligible for automatic extension if they have their previous visa stamp, plus the stamped I-20 or DS-2019, and the I-94 card or I-797A documenting that the change of status was approved by USCIS.
To qualify for Automatic Extension of the Validity of the visa, F and J visa holders should be in possession of the following: