As an international student and if you plan to stay in Austria for studies for less than six months. You will need to apply for a student visa in Austria at your nearest Austrian Embassy or Consulate of your country of origin.
It is compulsory for you to register with the municipal authorities (Meldeamt; Gemeindeamt, Magistratisches Bezirksamt); within three working days after entering the country. You will need a registration form that is available online or at the registration offices which must be completed by you and signed by your landlord.
Registration with the registration office is not needed if you reside in tourist accommodation (e.g. hotel, guest house, campsite, private room, Airbnb); for a maximum of 2 months.
For international students, there are two types of Austrian student visas; a Short-term visa and a Long-term visa. You should apply for the type of visa which suits the length of your study program:
Visa C (Short-term)
This is a short-term visa that allows you to stay and study in Austria; and in all other Schengen countries for a maximum of 90 days (3 months). It is not necessary if you are allowed to enter Austria without a visa.
Visa D (Long-term)
This is a long-term visa that is valid for up to six months and at least 91 days; and which you can then switch to a Student Resident Permit. This is the type of visa you need if you will pursue higher education or long-term studies in Austria. It is not necessary if you are a Japanese national.
Both visas, C and D, are free of charge for students.
Since the majority of international students mostly aim to stay in Austria for more than 6 months for study purposes. What you need to do in that case is to apply for a Student Residence Permit (Aufenthaltsbewilligung – Student); which will enable you to stay in the country for more than 6 months. Contact your nearest Austrian Embassy and also OeAD through this link for additional information.
Student visa in Austria applications can be submitted before your arrival only in the official Austrian Representations. You can find the closest one to you here. This authority is the only one responsible for issuing your visa/Residence Permit. It is important to apply as soon as possible, even 3 to 6 months before your estimated arrival.
Keep in mind that renewals of student visas are not allowed in Austria.
Overall, your student visa will be processed within 1-4 weeks depending on the volume of applications; and will cost you around 100 EUR.