U.S. citizens have new passport requirements for returning from Mexico from today. Basically, a traditional book-style passport is now required, but the U.S. government has also offered an alternative passport ‘card’ to make the adjustment easier.

New passport rules.

The changes apply as the Western Hemisphere Travel Initiative came into effect for trips to Mexico, Canada, Bermuda or the Caribbean.

Anyone entering or returning to the U.S. from those regions must show proof of citizenship, such as a passport book. Until now, passports had only been required for arrivals by air.

The new changes now apply to those returning by car or some cruise trips as well, but US citizens on "closed-loop" cruises (that begin and end at the same US port) will still be able to use just a birth certificate and government-issued photo ID.

The Department of State recommends passengers check with their cruise line to ensure they have the appropriate documents.

The new alternative passport card is like a driver's license and can save families time and money compared with the passport book.

However, if you come to Mexico by cruise or car, and are unlucky enough to have an emergency at home or get sick, you will need a traditional passport to fly back.

The new card may have some benefits, but the familiar passport book is still the safest option to go for.

For more information visit the US Department of State website.