United States citizens need an official US passport, valid for three months after the end of your stay. For example, a passport that expires on June 20, when your stay is until June 15 of the same year, will be rejected by customs officers. Unlike other European countries your passport does not need to be valid for a six month period to enter the country. If you are told otherwise ask to speak to a customs manager or call the tourist police. As well as your passport, you need to show proof (such as traveler's checks) that you have sufficient funds for the duration of your stay. Officially this is calculated as $80.50, or EUR62.40 per day, with a minimum of EUR561.60.
If you are a U.S. citizen and are going to Spain as a tourist you need documented proof of a hotel booking, known as a "Carta de Invitacion," or Invitation Card, which can be obtained from a local police station. This is a form that documents your name, address and dates of arrival and departure. If you are staying for up to three months (typically stamped as 90 days) in Spain you do not require a visa to enter the country. You can leave and re-enter the country over a period of six months, as long as you do not exceed your three month allowance. If you are staying for a consecutive period of over three months they you need to obtain a visa, typically a work visa. Gaining a work visa takes up to four months and requires you to have an official offer of employment from a Spanish business, as well as copies of your university or other educational transcripts and proof of your employer's tax and Social Security payments.
European Union citizens do not require a tourist visa to enter Spain and do not have any restrictions on their length of stay. If you are an EU citizen you can also work in Spain freely without a visa. However, working abroad for long periods may mean that you lose rights in your home country. For example, if you are from England and do not pay 30 years of work-based national insurance contributions then you will not receive a state pension when you retire.
