Travel Regulations for Canada, Mexico, or the Caribbean Islands
If you visit Canada, Mexico, or the Caribbean Islands (except for Cuba) for fewer than 30 days, you will need a valid passport and I-20, but not a valid visa stamp. You will be allowed to reenter the U.S. even if your visa has expired, provided you are in possession of a valid passport and I-20. Also, you should not surrender your I-94 card to authorities when you leave the U.S. Please note that if your visit will extend for more than 30 days, you must have a valid U.S. F-1 visa in order to reenter the U.S. The government of Canada or Mexico may require citizens from your country to have a visa before entering their countries.