VISA Requirements

International conference attendees traveling to the United States must secure proper entry clearance well in advance:

B-1 Visitor Visa: Most international travelers attending a scientific, educational, or professional conference will require a B-1 visa. The B-1 visa allows temporary entry to consult with business associates, negotiate contracts, or participate in professional conventions. Applications must be organized independently through a local U.S. Embassy or Consulate.
U.S. visa policy permits travel without a visa to citizens of specific countries if they meet requirements.
Visa Waiver Program (VWP) & ESTA: Citizens of participating Visa Waiver countries are permitted to travel to the U.S. without a visa for stays of 90 days or fewer. However, they must apply for and obtain pre-clearance web authorization via the Electronic System for Travel Authorization (ESTA) online before boarding their flight.
Border & Interview Documentation: To clarify the temporary nature of your trip to U.S. Customs and Border Protection (CBP) officers or consular staff, always print out and carry your SANER 2027 registration confirmation, proof of adequate financial support, and an official Conference Invitation Letter (available from the organizing committee upon request).
Letters of invitation are not required; however, the SANER 2027 organizers will provide you with a letter of invitation upon request.
Official Sources: U.S. Department of State - Visitor Visa Guidelines