All arriving passengers who intend to use the visa waiver program when travelling to the United States by air or sea must apply online for a travel authorization via the Electronic Travel Authorization System (ESTA) before departing, preferably at least 72 hours (3 days) in advance. This new requirement was announced on June 3, 2008 and aims to enhance U.S. security by pre-introducing participating VWP passengers against terrorist lists and/or no-fly lists and databases.  The electronic authorization, valid for a period of two years, is a reflection of the Australian Electronic Travel Authority system. Authorization is mandatory for citizens participating in the VWP prior to boarding flights to the United States, but, as with official visas, this does not guarantee entry to the United States, since the final registration permit at ports of entry to the United States is set by CBP officers. In order to qualify for an exemption from the VWP visa requirement, a traveller applying to enter the United States must be a citizen of a country designated by the U.S. Secretary of Homeland Security in agreement with the Secretary of State. Permanent residents of a given country who are not citizens of a particular country are not entitled to visa exemption. The criteria for designation as a country in the program are defined in Section 217 (c) of the Immigration and Nationality Act (Title 8.C No. 1187).  The criteria emphasize passport security and a very low refusal rate for non-immigrants, which does not exceed 3% in accordance with Section 217 (c) (2) (A) of the Immigration and Nationality Act, and which consistently complies with U.S. immigration law. British overseas nationals, because of their connection to the Turks and Caicos Islands, can enter the United States without a visa for short shops and holidaymakers.
 To qualify, they must not have had a criminal conviction or ineligibility in the past, not have violated U.S. immigration law, and must enter the United States on a direct flight from the territory. In addition, they must present a passport from the Turks and Caicos Islands, which states that they are a British overseas citizen and that they have the right to stay in the Turks and Caicos Islands. In addition to a valid non-expired passport, all travellers aged 14 and over must present a police certificate issued by the Royal Turkish Police and Icelandic Caicos within the past six months. All Overseas Territories of the United Kingdom Citizens of the Turks and Caicos Islands who apply for admission to a port of entry that does not have direct service to the territory must be in possession of a valid visa to enter the United States.