U.S. passport cards began being issued in 2008 to meet the needs of U.S. citizens who travel from Canada, Mexico, Bermuda, and Caribbean countries by land or sea. U.S. passport book can be used for Interantion travel by air, sea, or land. The U.S. passport card is valid for land and sea entry from Canada, Mexico, Caribbean, and Bermuda. NOT valid for international travel by air. The passport card is a cheaper alternative to the passport book. Passport books and cards are alternatives to a state-issued ID.