While a traditional blue passport book is the "gold standard," it is not strictly the only document allowed for U.S. citizens entering Canada via water or land in 2026. Under the Western Hemisphere Travel Initiative (WHTI), U.S. citizens can use an U.S. Passport Card, an Enhanced Driver’s License (EDL) (available in states like New York, Michigan, and Washington), or a Trusted Traveler Program card (such as NEXUS, SENTRI, or FAST) to board a ferry to Canada. However, if you are a U.S. Permanent Resident, you must carry your Green Card and, in most cases, a valid passport from your country of nationality. For anyone else, a valid passport and potentially an eTA or visa are required. It is vital to remember that a standard "REAL ID" driver's license is not valid for international border crossings; you must have one of the specific WHTI-compliant documents mentioned above to cross the maritime border.