Passport cards can be used as a valid ID document while travelling by sea in the US and the western hemisphere as a whole. Till last year passport card or passport book was not mandatorily being carried by a passenger on a cruise in that belt. But now it is very strict that all passengers should show their passport card or book before they board in to a ship. Now Passport card cruise and travel by land with it is compulsory by law. Beginning 2009, it became compulsory that passengers must carry their passport card with them while travelling by sea and while re-entering the US after a cruise.
Gone are those days when people used to re-enter US crossing the borders from Canada, Bermuda, Mexico and other Caribbean Countries, using their birth certificate, valid driving license etc.Now it is compulsory that people crossing the border even by land should show their valid passport card/book at the check points. It became effective from June I of 2009. Now people who have passport card can enter or re-enter the US proving his citizenship in the US.
The use of passport card helps the governments to curb the illegal immigration to certain extend. People can enter the US from Mexico and Canada by just showing some of his original or fake ID proof. Now passport card is the only acceptable ID proof to enter the US by sea or land. So in a cruise in the US or Caribbean Islands, all cruise organizers are warned to check the passports of their clients before organizing any cruise there. Even during a cruise in the US, on an emergency to get back home by air lift, one has to have a valid passport. Because a passport card/booklet proves his/her identity of citizenship in the US. It is best to have a credit card sized passport card on a cruise in the U.S. Use of passport card is more common among the people who do not have frequent international travel.
So a passport card cruise is safer and more secure than travelling with a passport booklet which is of bigger in size and need a separate bag or wallet to carry it. To get a passport card is as simple as getting a Passport booklet. Application and the process of both are same. Documents required for both are also same in nature. Since the passport card carries a radio frequency chip on it, the identity of a citizen can be easily proved and the unique number on passport card carries is directly attached to the database of the government. Use of passport card will prove your identity in some other fields also. When you go to government office /federal building you can directly enter there showing this card. At the time of some emergency, passport card would help you as a solid ID proof.
So before you pack up for a cruise in the US, please make sure that your passport card is inserted in your wallet without fail.