 Due to one of those strange legacies of colonialism, American Samoa is officially an unincorporated territory of the United States. American Samoans don't get full US citizenship, but they travel internationally on US passports. However, not many of them actually have a passport. You can travel between the two Samoan nations and the other countries in the region with what they call a CI document, or certificate of identity. So most people just get by with that.