Find out about Electronic Travel Authorization (eTA) - Canada .ca. Canada Customs What You Need to Know About Visiting Canada From the U.S. BY JANE MCLEAN Updated 10/02/19 Passport requirements have been a complicated and ever-changing issue for U.S. travelers to Canada due to the Western Hemisphere Travel Initiative (WHTI), which was introduced in 2004 by the U.S. government to strengthen U.S. border security and standardize travel documentation. Visitors from any country other than the U.S. have always needed a passport to enter Canada. On the other hand, because of a friendly border crossing agreement between Canada and the United States, Canada Border Services did not require U.S. citizens to present a passport to enter Canada. This friendly border crossing agreement used to be mutual; however, now the WHTI requires that U.S. citizens have a passport to return home via air.