A visa is a conditional authorization granted by a polity to a foreigner that allows them to enter, remain within, or leave its territory. Visas typically include limits on the duration of the foreigner's stay, areas within the country they may enter, the dates they may enter, the number of permitted visits, or if the individual can work in the country in question. Visas are associated with the request for permission to enter a territory and thus are, in most countries, distinct from actual formal permission for an alien to enter and remain in the country. In each instance, a visa is subject to entry permission by an immigration official at the time of actual entry and can be revoked at any time. Visa evidence most commonly takes the form of a sticker endorsed in the applicant's passport or other travel document but may also exist electronically. Some countries no longer issue physical visa evidence, instead recording details only in immigration databases.
The Visa Waiver Program (VWP) is a program of the United States federal government that allows nationals of specific countries to travel to the United States for tourism, business, or while in transit for up to 90 days without having to obtain a visa. It applies to all fifty U.S. states, the District of Columbia, Puerto Rico, and the U.S. Virgin Islands, as well as to Guam and the Northern Mariana Islands, which also have an additional program with waivers for more nationalities; American Samoa has a similar but separate program.
The visa policy of Australia deals with the requirements that a foreign national wishing to enter Australia must meet to obtain a visa, which is a permit to travel, to enter and remain in the country. A visa may also entitle the visa holder to other privileges, such as a right to work, study, etc. and may be subject to conditions.
Visitors to the United States must obtain a visa from one of the U.S. diplomatic missions unless they are citizens of one of the visa-exempt or Visa Waiver Program countries.
The Electronic System for Travel Authorization (ESTA) is an automated system that determines the eligibility of visitors to travel to the United States under the Visa Waiver Program (VWP). ESTA was mandated by the Implementing Recommendations of the 9/11 Commission Act of 2007. ESTA only authorizes travel to a U.S. airport, border, or port of entry, but admissibility into the United States is determined by a U.S. Customs and Border Protection (CBP) officer upon arrival. The ESTA application collects biographic information and answers to VWP eligibility questions.
The visa policy of the Schengen Area is a component within the wider area of freedom, security and justice policy of the European Union. It applies to the Schengen Area and to other EU member states except Ireland. The visa policy allows nationals of certain countries to enter the Schengen Area via air, land or sea without a visa for up to 90 days within any 180-day period. Nationals of certain other countries are required to have a visa to enter and, in some cases, transit through the Schengen area.
The visa policy of mainland China deals with the requirements which a foreign citizen wishing to enter the mainland of the People's Republic of China must meet to obtain a visa from one of the Chinese diplomatic missions, which is a permit to travel to, enter, and remain in the country. Visa exemptions are based on bilateral agreements and unilateral decisions.
The visa policy of Canada requires that any foreign citizen wishing to enter Canada must obtain a temporary resident visa from one of the Canadian diplomatic missions unless they hold a passport issued by one of the 53 eligible visa-exempt countries and territories or proof of permanent residence in Canada or the United States.
The visa policy of South Korea allows citizens of certain countries to enter South Korea with a Korea Electronic Travel Authorization (K-ETA)
The visa policy of the United Kingdom is the policy by which His Majesty's Government determines visa requirements for visitors to the United Kingdom and those seeking to work, study or reside there. The visa policy of the UK also applies to the Crown dependencies of Guernsey, Jersey and the Isle of Man, which each operate their own immigration enforcement and have separate work permit systems. The visa policy does not apply to any of the British Overseas Territories, who generally apply their own visa policies.
The visa policy of Malaysia consists of the requirements for foreign nationals to travel to, enter, and remain in Malaysia. Most visitors to Malaysia are granted visa-free entry for a period of 90, 30, or 14 days respectively. However, nationals from some countries must first obtain a visa from one of the Malaysian diplomatic missions around the world before being allowed into the country.
Visitors to Thailand must obtain a visa from one of the Thai diplomatic missions unless they are citizens of one of the visa-exempt countries, or citizens who may obtain a visa on arrival, or citizens eligible for an e-Visa.
The visa policy of Singapore deals with the requirements a traveller must meet to enter Singapore. A foreign national, depending on their country of origin, must meet certain requirements to obtain a visa, which is a permit to travel, to enter and remain in the country. A visa may also entitle the visa holder to other privileges, such as a right to work, study, etc. and may be subject to conditions.
Visitors to Azerbaijan must obtain a visa from one of the Azerbaijani diplomatic missions unless they are citizens of one of the visa-exempt countries, or citizens eligible for an electronic visa on arrival, or citizens eligible for an electronic visa.
Most visitors to Iran must obtain an electronic visa (e-Visa) prior to their arrival in Iran, unless they are a citizen of one of the visa-exempt countries or countries that are ineligible for an e-Visa, in which case they must obtain a visa in advance from one of the Iranian diplomatic missions around the world.
Visitors to Argentina must obtain a visa from one of the Argentine diplomatic missions unless they are citizens of one of the visa-exempt countries.
Kenya has abolished visa requirements for all foreign visitors from 1 January 2024, and instead implemented an Electronic Travel Authorisation (eTA) system.
The British Overseas Territories maintain their own entry requirements different from the visa policy of the United Kingdom. As a general rule, British citizens do not have automatic right of abode in these territories.
The European Travel Information and Authorisation System (ETIAS) is a planned electronic authorisation system of the European Union for visa-exempt visitors travelling to the Schengen Area, as well as Cyprus. ETIAS is planned to cost €7 for 3 years validity or until the expiry of the passport, whichever is sooner. As of August 2024, the ETIAS is planned to come into force by May 2025 with a planned six-month transition period.
An electronic visa (E-Visa) and an electronic travel authorization are digital travel permits commonly required in conjunction with a valid passport for entry into specific jurisdictions. These electronic travel documents have gained prominence in the modern era of digital connectivity and streamlined travel processes.
United Kingdom 
