No visa is required for citizens of countries of the European Union.
Spain has an agreement for visa exceptions with many countries, such as: Argentina, Australia, Brazil, Canada, Chile, Costa Rica, Croatia, Guatemala, Israel, Japan, Malaysia, Mexico, Monaco, New Zealand, Nicaragua, Panama, Paraguay, San Marino, Switzerland, Uruguay, USA, Venezuela. Citizens from these countries do not need a visa to enter and stay in Spain up to 90 days.
Citizens from all other countries do need a tourist visa to enter Spain. This kind of visa provides coverage for attending scientific conferences, seminars or meetings.
In order to request a tourist visa, you have to contact the Spanish Embassy/Consulate nearest to your city.
This must be done several months before the conference is set to take place, since visa applications can take quite some time.
Letter of Invitation
Full name, passport number and country of issue.
Institution and preliminary title of communication.
Full mailing address and a fax number to send the letter.
Names and passport numbers of your accompanying persons, if any.
Please, be sure to provide your name and the names of your accompanying persons exactly as written in the passports.