Even if you are only in transit through the USA, you are required to pre-apply for ESTA approval. An ESTA simply checks and approves a person, giving them permission to travel to the United States, but it does not guarantee entry to, or transit through the US. However, if you are from one of the 38 visa waiver countries within the ESTA program, and fill in the application truthfully, it is unlikely that you would be denied entry or transit through the US. If you travel to the US and are denied entry, for whatever reason, you will never be able to apply for ESTA again. You will have to apply for a visa, such as a B-2 tourist visa which will be issued through the US Embassy in your home country.
If you are transiting through the USA en route to another international destination you will need ESTA approval in order to board the plane or ship. In this case, as part of your ESTA application, you should answer “Yes” to the question "Is your travel to the US occurring in transit to another country?"
Travelers to destinations such as Mexico, Canada, the Caribbean Islands, Central or South America often have to transit though the US and connect with another flight. If you do not wish to transit through the US, you need to find another direct travel option that does not include touchdown in the US. However, if you are eligible for the Visa Waiver Program (VWP), it is very easy to apply online for an ESTA to cover your transit through the USA. Onward travel to Canada by air (only) now requires travelers to have an Electronic Travel Authorization, known as an eTA. More details can be found on the Government of Canada website.START APPLICATION >