Citizens of most countries in the world need a passport valid for at least three months as well as a visa to visit Austria. There are some exceptions:
Austria is in the Schengen area. Travel visa issued for one Schengen country (i.e., a visa from one of the countries of the Schengen agreement establishing mutual visa recognition between those European countries) are usually valid for all Schengen countries. More information about Schengen visa can be found here. If you have such a visa (e.g., from attending another conference which is also in the Schengen area), please contact your local Austrian consulate to learn if your Schengen visa is valid for Austria, as well as about all immigration requirements for your trip.
International registrants should be particularly aware and careful about visa requirements, and should plan travel well in advance. All visa inquiries should be directed to the local Austrian consulate. Please send your request for a letter in support of a visa application to the TCCA Chair, Professor Lieven Eeckhout (Lieven dot Eeckhout at UGent dot be). Your request should include your name, mailing address, and e-mail, and authors of papers should include the title of their accepted submission. Please register for the conference prior to requesting a support letter and include a copy of the registration confirmation in your request, since HPCA 2018 can only issue letters for confirmed registrants.