Most foreign nationals entering the United States on a temporary basis as nonimmigrants are required to first obtain a visa at a U.S. consular post abroad. A visa grants its holder permission to apply for admission to the United States. The visa does not guarantee admission, however.

Most foreign nationals entering the United States on a temporary basis as nonimmigrants are required to first obtain a visa at a U.S. consular post abroad. A visa grants its holder permission to apply for admission to the United States. The visa does not guarantee admission, however. All nonimmigrants remain subject to inspection and admission by U.S. Customs and Border Protection (the guys in blue uniforms) at the port of entry.

There are some exceptions to the visa requirement. The biggest exception is that Canadian citizens are visa-exempt in all nonimmigrant classifications except for K and E. The second major exception is the Visa Waiver Program, which permits nationals of certain countries to enter the U.S. without a visa for up to 90 days as visitors. There are other, more limited exceptions, such as those who qualify for humanitarian parole.

While a visa must be valid at the time of entry to the United States, it need not remain valid for the duration of the foreign national's stay in the United States. The person's period of authorized stay is governed, instead by his I-94 Arrival/Departure Record. So long as a foreign national's I-94 remains valid and he otherwise abides by the terms of his nonimmigrant classification, he is considered to be maintaining status, even if his visa is expired. He is only required to obtain a visa if he departs from the U.S. temporarily and thereafter seeks readmission as a nonimmigrant.

There is a very limited subset of nonimmigrants, however, who can use “Automatic Visa Revalidation” to return to the United States on an expired visa. Automatic Visa Revalidation applies to foreign nationals who:

• Are in possession of an unexpired I-94 Form (F-1s must have a currently valid I-20 and J-1s must have a currently valid DS-2019 in addition to their I-94 authorized D/S);
• Are applying for readmission after an absence not exceeding 30 days solely in a contiguous territory (or in the case of those in F or J-1 status, to a contiguous territory or adjacent island (link to: http://www.ice.gov/sevis/travel#_Toc81222015) other than Cuba);
• Note: this means that you cannot use automatic visa revalidation if you drive to Canada, fly overseas, fly back to Canada and attempt to return to the U.S.
• Has maintained and intends to resume nonimmigrant status;
• Note: the status in which the alien intends to return to the U.S. must be the same classification he was in at the time of departure, but need not be the same classification for which the expired visa was issued. For example, if someone entered the U.S. in F-1 status, and changed status to H-1B, but never obtained an H-1B visa, he may still use automatic visa revalidation to enter the U.S. to resume H-1B status.
• Is applying for readmission prior to expiration of the initial admission or extension of stay (or change of status);
• Possesses a valid passport;
• Does not require a nonimmigrant waiver;
• Has not applied for a new visa while abroad; and
• Note: this means that foreign nationals who travel to Canada or Mexico to apply for a new visa as a third country national may not take advantage of automatic visa revalidation to return to the U.S. in the event their visa is denied or if visa issuance is delayed due to security clearances. This is a big risk in applying for a visa as a third country national; it means that the applicant cannot return to the U.S. but must depart directly from Canada or Mexico to their home country to reapply for the visa, unless they can obtain a waiver of the visa requirement at the port of entry, on Form I-193, at CBP's discretion.
• Is not a national of a state sponsor of terrorism.

It should be noted that automatic visa revalidation is available even for holders of single or limited entry visas. For example, K-1 fiancée visa holders are always given a single-entry visa, meaning that, once they enter the U.S., they typically cannot leave the U.S. until they adjust their status to permanent resident or receive an advance parole travel document. However, automatic visa revalidation is a very limited exception to this rule. Moreover, nationals of certain countries (most notably, China) are often given visas with a limited number of entries to the U.S. For these individuals, automatic visa revalidation gives them the chance to do some limited traveling outside of the U.S. in North America.

Note, however, that automatic visa revalidation is only available where the initial visa has already expired. It is not available where a visa is unexpired but is endorsed for only a limited number of entries.

It is also important to note that automatic visa revalidation applies only to individuals who have visas. Thus Canadian citizens, other than those in E or K status, are never eligible for automatic visa revalidation because there is no visa to revalidate. Similarly, those individuals who used the Visa Waiver Program to enter the United States are ineligible to use this provision.