In Plain English
I-94 = Immigration Status and Length of Stay
Visa = Permission to Enter
I-94 Arrival/Departure Record
An I-94, now issued electronically by Customs and Border Protection, is proof that the foreign national was admitted into the U.S. legally. It controls how long the foreign national can legally remain in the U.S., his or her authorized non-immigrant status, and the date by which he or she must depart the U.S. A new I-94 is issued each time a foreign national is permitted to re-enter the U.S. or each time he or she receives an approval notice to extend his or her stay.
A Visa is the stamp in a passport that permits a foreign national to seek entry at the U.S. border within a specified timeframe. Once the foreign national is granted admission to the U.S., the visa is of no importance. If the visa-holder leaves the U.S. while the visa is still valid, he or she may seek re-entry with the same visa as long as it permits multiple entries. If the foreign national leaves the U.S. after the visa has expired, he or she must apply to the U.S. Embassy or Consulate for a new visa.
By Way of Example
Juan is a citizen of Mexico. While in Mexico, he receives a job offer in the U.S. Juan accepts the offer and applies to the U.S. Consulate in Juarez for a TN Visa. He schedules an interview for October 22, 2014 and takes all of the required documentation to obtain his Visa. After the Consular Officer conducts the interview, she determines that Juan satisfies all of the requirements to seek entry into the U.S. and stamps his passport with a Visa valid until October 21, 2015. On November 2, 2014, Juan seeks entry into the U.S. at a port of entry. The Customs and Border Protection Officer inspects Juan’s passport and visa and questions him about his reason for seeking entry into the U.S. After inspection, the CBP Officer grants Juan admission to the U.S. but does not give him any documents. Instead, the CBP Officer stamps his passport with the admission date, the class of admission, and the date that he admitted until, November 1, 2017. She tells Juan that he can access his electronic I-94 admission record online and encourages him to retain a copy for proof of legal immigration status and work authorization. Juan enters the U.S. and begins work on November 10, 2014.
Juan decides he will return to Mexico on December 20, 2014 to spend the holiday with his family. Upon exiting the U.S., CBP records his departure via the electronic manifest provided by his airline. Juan enjoys the holidays with his family and then boards a flight back to the U.S. to return to work. When he lands, the CBP Officer inspects his passport and visa and grants him admission to the U.S. until November 1, 2017. The CBP Officer tells Juan he can retrieve his electronic I-94 online. Juan then enters the U.S. and returns to work.
After nearly a year has passed, Juan again decides to return to Mexico to spend the holiday with his family. Although Juan’s Visa expired on October 21, 2015, he still held legal status because his I-94 is valid until November 1, 2017. Again, CBP records his departure, but takes no action because he stayed in the U.S. past October 21, 2015. Before departing the U.S., Juan pre-scheduled an interview at the U.S. Consulate to renew his visa because he knew his prior visa had already expired. At the visa interview on January 2, 2016, the Consulate Officer issues a new Visa that will expire on January 1, 2017. Juan presents his Passport and Visa to the CBP Officer when he seeks entry into the U.S. The CBP Officer inspects his documents and grants him admission to the U.S. He tells Juan that he can retrieve his I-94 online and stamps his passport with the admission date, the class of admission, and the date that he admitted until, November 1, 2017.