A transit visa allows you to enter a country temporarily to change flights or catch another form of transport to your onward destination. These visas are often essential if your passport is not eligible for visa waivers or other online visa alternatives in the country in question.

An airport transit visa (ATV) is a specific type of short-term authorization that allows a traveler to pass through the international transit zone of an airport in a foreign country without officially entering that country’s national territory. This is common in the Schengen Area and the US (C-1 visa). It is designed for passengers who have a layover and are simply switching planes to reach a third country. Crucially, an ATV does not allow you to leave the airport, clear customs, or stay overnight in a hotel outside the terminal. If your connection requires you to change terminals that are not linked "airside," or if you need to re-check your bags, you would likely need a standard visitor visa instead. Requirements vary wildly by nationality and the specific transit country, so it is vital to check if your passport requires one even if you never intend to step foot outside the terminal gates.