United States policy permits people from certain countries to travel to the United states without the need for a US Visa. These would be as follows. Always speak to a US Immigration lawyer in Thailand before you start the K1 Visa process.
Visa Waiver Program (VWP)
The Visa Waiver Program (VWP) enables foreign nationals of the countries listed below to travel to the US for both tourism and/or business with stays of 90 days or less permitted without having obtained a visa. The Visa Waiver Program was created in 1986 with the primary objective of eliminating the barriers to travel. This would stimulate a number of industries but more so the tourism industry. This also permitted the US Department of State to focus consular resources in other areas. Visa Waiver Program eligible travelers may however apply for a visa, if they prefer having one. Having said that not all Visa Waiver program travelers are eligible to use the program. All Visa Waiver program travelers are screened well prior to admission into the US, and they are enrolled in the Department of Homeland Security US VISIT program.
These are the countries listed in the VWP:
The following conditions apply for the Visa Waiver program:
1. The purpose of your stay in the US is 90 days or less for tourism or busines.
2. You present a machine-readable passport.
3. Depending on when VWP travelers’ passports were issued, other passport requirements will apply.
4. You have not been found ineligible for a U.S. visa
5. You can demonstrate sufficient funds to support yourself.