As of January 23, 2007, ALL U.S. citizens travelling by air between the United States and the Caribbean, Canada, Mexico, Central and South American, and Bermuda, will be required to present a valid passport. 

On October 1, 2007, ALL U.S. Citizens traveling outside the United States by air will be required to present a valid passport to enter and depart from the United States; as the summer accommodation period has passed. 

This requirement will be extended to sea travel, including ferry service, by the summer of 2008.  Until then, travelers returning from the Cayman Islands by sea must have government-issued photo identification and a document showing their U.S. citizenship (for example, a birth certificate or certificate of nationalization).  Further information on upcoming changes to U.S. passport policy can be found on the Bureau of Consular Affairs web site at http://travel.state.gov/travel/cbpmc/cbpmc_2223.html.  We strongly encourage all American citizen travelers to apply for a U.S. passport well in advance of anticipated travel.  American citizens can visit travel.state.gov or call 1-877-4USA-PPT (1-877-487-2778) for information on how to apply for their passports. 

All sectors of the Cayman Islands Department of Tourism have been working together this year with partners both locally and in the U.S. to make sure all travellers to Cayman - past, current and future - are conscious of the passport regulations. 

Background of the US Passport Initiative:
http://travel.state.gov/travel/cbpmc/cbpmc_2223.html

Getting a New Passport:
http://travel.state.gov/passport/get/first/first_832.html

Renewing your Passport:
http://travel.state.gov/passport/get/renew/renew_833.html