What is a transit visa? At its core, a transit visa is a travel authorization that allows travelers to go through one country to get to another. Usually used for air travel, transit visas can also be required for some sea travel, too. Usually lasting for 12 hours or less, these visas are only meant for temporary layovers in one country, and they usually do not permit travelers from leaving the airport. Who needs a transit visa/permit? This topic can get complicated because there is no standard; some countries require transit visas for citizens of certain countries, while another country might require transit visas for citizens of an entirely different list of countries.