All international students should allow 2-3 months for visa application processes. In order to acquire either a F-1 or J-1 student visa, it is necessary to have an appointment with a visa official at the nearest U.S. Embassy or Consulate. You are required to pay the U.S. government SEVIS fee to make this appointment, and to bring your application materials, admission offer, passport and immigration documents issued by the university to the appointment. It is best to try to receive this visa as soon as possible after your admission. More detailed instructions on how to apply for your visa will be sent to you upon admission to CU Boulder, along with your admission offer.
The following websites are good resources for incoming international graduate students: