Usually, yes. Unlike Puerto Rico, Guam, or the U.S. Virgin Islands, American Samoa runs its own immigration and border controls, so U.S. citizens and nationals must show either a valid U.S. passport or a certified birth certificate proving U.S. nationality to enter. You also need a ticket for onward travel out of American Samoa, or proof of employment there.
A REAL ID or driver’s license alone is not enough. If you travel with a birth certificate instead of a passport, bring a government-issued photo ID with it. Once admitted, visitors can stay up to 30 days, and the territory’s Attorney General can approve an extension of up to 30 more days.
Source: U.S. Department of the Interior, Office of Insular Affairs, “American Samoa”.
Image: Pago Pago Harbor by Tavita Togia, National Park Service (public domain), via Wikimedia Commons.