Yes. Any American traveling to Cuba will need a valid U.S. passport. It's suggested that your passport be valid for at least six months after traveling on an insightCuba tour. Please be sure to check the expiration date of your passport, and if need be, renew your passport if it is nearing expiration.
For information on renewing your U.S. passport by mail, please visit the U.S. Department of State website.
To apply for a U.S. passport through the U.S. Postal Service, click here.
For general information about U.S. passports, click here.