Do I need to apply for ESTA if...?

I am a citizen of Canada?
No, citizens of Canada who are traveling with a Canadian passport do not need an ESTA.

I am a Landed Immigrant of Canada?
If you are a landed immigrant of Canada and a citizen of a country that participates in the Visa Waiver Program (VWP), and you enter the U.S. by land, ESTA is not required. If you do not have ESTA, you will be required to complete the paper I-94W form and proceed through a manual entry process at the land border crossing. If you have an approved ESTA when entering the U.S. at a land border crossing, you will not be required to complete the paper I-94W form and your entry process is expedited. If you are coming to the U.S. by air or sea, you DO have to apply for ESTA. If you are not a citizen of a VWP country, you are required to have a visa, and therefore ESTA does not apply to you.

I am a Lawful Permanent Resident of the United States and a citizen of a VWP country?
No.

I am a citizen of a VWP country and am visiting the U.S. from Canada or Mexico?
If you are a citizen of a country that participates in the Visa Waiver Program (VWP), and you enter the U.S. by land from Mexico or Canada, ESTA is not required. If you do not have ESTA, you will be required to complete the paper I-94W form and proceed through a manual entry process at the land border crossing. If you have an approved ESTA when entering the U.S. at a land border crossing, you will not be required to complete the paper I-94W form and your entry process is expedited. However, if issued, you should return your green I-94W card upon departure from the U.S. If you are arriving by air or sea, you do need to apply for ESTA.

I am a citizen of a VWP country and am traveling to the United States by air to transit the U.S.?
Yes. You must apply for ESTA even if you are only transiting the U.S. In the address field of the application, write "In Transit."

I have dual citizenship from both a VWP country and a non-VWP country?
If you are flying under the terms of the VWP, with your VWP passport, you must apply for ESTA. If you are using your non-VWP country s passport, you will require a visa and therefore ESTA does not apply to you.

I am a citizen of a VWP country and am going to Guam or Commonwealth of the Northern Mariana Islands (CNMI)?
For international travel to Guam/CNMI under the VWP, ESTA is required. Nationalities that are eligible for Guam/CNMI VWP can travel to Guam/CNMI under that program without an ESTA. However, under the Guam/CNMI VWP, the maximum stay is 45 days and stay is restricted to those islands only - travel cannot be to the United States.
Travel from the United States to Guam/CNMI is considered a domestic flight, so no ESTA is required. Travelers go through pre-inspection for travel from Guam/CNMI to the United States. If that travel is under VWP, they need an ESTA.

I am a citizen of a VWP country and am traveling for short-term business or tourism under the VWP to Puerto Rico or the U.S. Virgin Islands?
Yes, ESTA is required for travel to these locations.

I am traveling with a minor (child under age 18) who is a citizen of a VWP country?
If the minor is traveling to the United States under the VWP as a tourist 90 days or less, he/she is required to obtain an independent ESTA approval.

I am a U.S. Citizen with dual citizenship in a VWP country?
U.S. Citizens are not required to have an ESTA and are required to use their U.S. passport to travel to the U.S.

If I have a current, valid visa?
Individuals who possess a valid visa will still be able to travel to the United States on that visa for the purpose for which it was issued. Individuals traveling on valid visas are not required to apply for an ESTA authorization.