As of January 8, 2007, the U.S. government requires that all adults and children (even newborns) to have a valid passport for all international travel by air.
This regulation also applies to travel to the Bahamas. For information on how to get or renew a passport please visit http://travel.state.gov/
It can take up to 6 weeks or longer to get a passport so now is the time to do it.