Greyhound Can Make Your Next Trip Even Easier Tickets by mails. Avoid lining up altogether, by purchasing your tickets in advance, and having them delivered right to your mailbox. Just call Greyhound at least 10 days before your departure (1 - 800 - 231 - 2222). Prepaid tickets. It is easy to purchase a ticket for a friend or family member no matter how far away they may be. Just call or go to your nearest Greyhound terminal (票务点) and ask for details on how to buy a prepaid ticket. Ticketing requirement. Greyhound now requires that all tickets have travel dates fixed at the time of purchase. Children under two years of age travel free with an adult who has a ticket. If your destination (目的地) is to Canada or Mexico. Passengers traveling to Canada or Mexico must have the proper travel documents. U.S., Canadian or Mexican citizens should have a birth certificate, passport or naturalization (入籍) paper. If you are not a citizen of the U. S., Canada or Mexico, a passport is required. In certain cases a visa may be required as well. These documents will be necessary and may be checked at, or before, boarding a bus departing for Canada or Mexico. When people are traveling to Canada or Mexico, a passport is a must for ______.