We didn't look into it because we have sailed from Galveston to Cozumel, Belize and Roatan several times in the past few years and a driver's license and birth certificate and that was always accepted by the various cruise lines, Royal Caribbean, Norwegian and Carnival who owns Princess. I'm glad I read the fine print a couple of days ago. Tomorrow we are driving to the passport office in Dallas to get a last minute passport. We have an appointment and they have the ability to issue same day passports, thank goodness.