A tourist visa is required by foreign nationals who wish to travel to Iran for sightseeing purposes or to visit their friends and family. The visa allows you to stay in Iran for up to 30 days, although the duration of your visa is at the discretion of the Iranian Ministry of Foreign Affairs. At times they may only grant 12-day visas, even if you ask for four weeks. However, you can easily get a visa extension once you arrive in Iran, at no extra cost, by going to any police station, or the Aliens Office in Tehran.