If you stay in Korea for more than 90days, you should have the ARC according to
Immigration Act. It is evidence to prove that you have a right to stay in Korea
within valid. If you have ARC, you do not need to bring your passport all the time.
Those intending to stay in Korea for more than 90 days after entry
A former Korean who have acquired a foreign nationality after losing the Korean one or
a foreigner born in Korea, who are given residence status and intend to
stay for more than 90 days.