You can enroll for course implementations in spring and autumn once the registration period has started. The enrollment is done in Sisu (instructions for registration).

Make sure to enroll for course implementations on time. Once the registration period has ended, you will need permission from the teacher to attend the course.

You can only enroll for courses that have been added to your personal study plan. First, search for and add the course to your personal study plan, obtain approval from your tutor teacher if separate approval is required, and then enroll for the specific implementation of the course you have selected. 

Student academic calendars for the academic year can be found here.