There are currently 40 countries belonging to the Visa Waiver Program: Andorra, Australia, Austria, Belgium, Brunei, Chile, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Japan, Latvia, Liechtenstein, Lithuania, Luxembourg, Monaco, Netherlands, Poland, New Zealand, Norway, Portugal, Republic of Malta, San Marino, Singapore, Slovakia, Slovenia, South Korea, Spain, Sweden, Switzerland, Taiwan, and the United Kingdom
However, under the following circumstances, generally eligible citizens cannot apply for ESTA:
- Absence of electronic passport (with chip)
- Intention to work in the United States, paid or unpaid, (including au pair or internship work)
- Intention to stay in the United States for more than 90 days
- Intention to attend school or college in the United States
- Current or previous possession of uncanceled green card via appropriate I-407 form
- Refusal of admission or has been deported from the United States within the past 5 years
- Denial of one's U.S. visa due to an ineligibility other than 221(g) or 214(b) of the Immigration and Nationality Act
- Arrest or conviction for any felony or misdemeanor (including drug trafficking)
- Has been afflicted with a serious communicable disease or state of drug addiction
- Participation in the persecution of any person under the control of the Nazi German government
- Association or affiliation with any terrorist organization
Travelers who fall into one or more of these categories are not necessarily inadmissible for entry into the United States but
must apply for and obtain an ordinary visa before traveling to the United States