ESTA (Electronic System for Travel Authorization) is a requirement for citizens or nationals of ESTA Visa Waiver Program (VWP) countries to travel to the United States for tourism or business for stays of 90 days or less without a visa. If you are a citizen of a VWP country and plan to enter the United States without a visa for tourism or business purposes, you will need to obtain an ESTA.

It’s important to note that ESTA is mandatory for all eligible citizens or nationals of VWP countries traveling to the US for tourism or business for stays of 90 days or less under the Visa Waiver Program (VWP). If you’re coming to the US for other purposes like study, work, or permanent residence, then you would need a different type of visa and can’t travel under the VWP.

It’s also worth noting that certain individuals are not required to obtain ESTA, such as crew members of a carrier, certain government officials, and individuals with valid A, G, C-2, C-3, NATO, or diplomatic visas.

ESTA also does not apply for visitors from countries that are not eligible for the VWP, such as those travelers who are citizens of Cuba, Iran, North Korea, Syria, Venezuela, Bangladesh, Eritrea, Kyrgyzstan, Myanmar, Nigeria, Sudan, and Tanzania. These travelers need to obtain a visa in order to enter the United States.