Your passport must be valid at least six months into the future at all times, especially upon initial entry or re-entry to the U.S. If yours will expire soon, contact your home country's embassy in the U.S.
U.S. Entry Visa
The visa stamp in your passport should be valid on the date of your return to the U.S. (It does not, however, need to remain valid during your stay in the U.S.) If you have an old, expired passport with a valid U.S. entry visa, you do not need to get a new visa stamp in your new passport as long as you carry both passports when you enter the U.S. Canadian citizens do not need a U.S. visa. Canadian landed immigrants, however, are required to obtain U.S. entry visas. See also Understanding Your Visa.
A J-1 Exchange Visitor should only enter the U.S. with a visa showing the school's (or program) name noted on it, even if the visa has not yet expired. If you change schools, obtain a visa with the new name noted on it before entering or re-entering the U.S.
In certain cases, visitors may be able to re-enter the U.S. with an expired visa after a short trip to Canada/Mexico using Automatic Visa Revalidation.
Evidence of Financial Support
It is strongly recommended that F/J non-immigrants carry proof of the financial support and resources reflected on the Form I-20 or DS-2019.
I-20 or DS-2019 (F-1/F-2, J-1/J-2 documents)
Make sure your original form I-20 or DS-2019 has been PROPERLY ENDORSED by the school official or agency that issued the document. For current students, an I-20 or DS-2019 travel endorsement is valid for 12 months, or until the expiration of the document, whichever is first. Berkeley International Office generally recommends that the signature be current within 10 months of your re-entry date. ( Please note: Those on F-1 OPT must have the endorsement within past 6 months). If UC Berkeley issued your I-20 or DS-2019, bring it to Berkeley International Office for endorsing. Those with an I-20 or DS-2019 issued by another program sponsor will need to contact that sponsor at least two or three weeks before departure to obtain the necessary travel signature.
It is also recommended that students travel with proof of the current or next semester's registration (e.g.,printout of full-time class enrollment or Enrollment Verification from Cal Student Central).
F-1 Students on Post-completion OPT should see OPT Travel Information. J-1 students on post-completion Academic Training should see Academic Training Travel Information for additional documents needed.
SEVIS (I-901) Fee Payment
If there are any problems during entry, please notify Berkeley International Office as soon as you arrive.