You must apply for an alien registration card(ARC) at Seoul immigration office within 90 days from the date of entry.
A group application is arranged at the beginning of each semester.
Staying in Korea for more than 90 days without completing alien registration is illegal.
The ARC is valid only for the duration of your exchange program, and even if the card shows a later expiration date, your visa will be terminated once the semester ends. (If you wish to extend your stay for Korean language course during the vacation or for traveling in Korea, it is possible to extend your visa for up to one month.)
Except for opening a bank account or signing up for a mobile phone plan, you must not share your ARC or alien registration number with anyone else.
If you lose your ARC or if your residential address changes, you must report it to the relevant authority within 14 days.