Before traveling to a POE, what must aliens secure?

To travel to a Port of Entry (POE) into the United States, aliens are generally required to secure a visa. A visa is an official document issued by a U.S. embassy or consulate that allows a foreign national to apply for entry into the U.S. It specifies the purpose of travel, whether for tourism, business, work, or study, and includes the conditions under which the traveler can enter the country.

While a passport is indeed necessary for international travel, it functions as an identification and travel document rather than permission to enter the U.S. Travel insurance can be beneficial but is not mandated for entry, and an immigration waiver applies to specific circumstances where an individual may have previously violated immigration laws. Therefore, securing a visa is fundamental for an alien before planning to travel to a POE, making it the correct answer.