Documents Required to Re-enter the U.S. in F-1 Status:
1. A valid passport
2. A valid F-1 visa stamp (except for Canadian citizens)
3. A valid I-20 with a valid travel signature.
All F-1 students are required to present an unexpired I-20 with a valid travel signature at the port of entry when returning to the U.S. from a trip outside the country. Travel signatures refer to the list of signatures on the second page of the I-20. The travel signature must be provided by an advisor in the Office of International Services.
Travel signatures are typically valid for one year. For F-1 students who are in a period of Optional Practical Training (OPT) following graduation, the travel signature is valid for only six months.
In addition to their valid passport and F-1 visa, F-1 students on OPT should have a travel signature that is no more than six months old as well as their Employment Authorization Document (EAD card) and a letter from an employer verifying that they have a job in the U.S.