Change of Substance of Registration

Any foreign national staying in Korea for 91 days or more must register as a resident alien. This includes periods of more than 90 days after losing Republic of Korea citizenship, acquiring foreign citizenship, or the birth of a foreign citizen. When you register as an alien, you are issued an Alien Registration Card. Your Alien Registration Card is needed in a variety of circumstances, and you are legally obliged to have it on your person. Alien registration should be done at the Immigration Office with jurisdiction for the area in which the applicant lives. The purpose of registering foreign nationals is for the fair supervision of resident foreigners, by clearly defining their residence and status. Citizens of the Republic of Korea are subject to the Resident Registration System.

New Registrations

Reasons for Re-Issuance
Apply for registration within the first 90 days in Korea, if you intend to stay for more than 91 days.
Documentation to Prepare
Your passport, three identical portrait pictures of yourself (3cm x 4cm, "the size of half a name card"), and 10,000won for government revenue stamp.
Issuing Process
When you apply, the immigration official at the registration window will make sure there are no problems with your application, and if there are none, issue you a receipt for your passport. You will likely be issued an Alien Registration Card within roughly a week. Your passport will be stamped with a stamp saying ¡°Registered Alien¡±
Fingerprinting
Foreigners in Korea must be fingerprinted at Immigration Offices in the following circumstances.
Foreign National Time of Fingerprinting
- Foreigner age 20 or more to reside in Korea more than one year. - When granted sojourn period over one year,

at the time of alien registration.
- Within 60 days of becoming 20 years of age.
- Foreigner in detention. - When ordered detained.
- Foreigner ordered deported. - When ordered deported.
- Foreigner of unclear identity being investigated for violation of the Immigration Law. - As investigated

Things to Remember
Foreign nationals over the age of 17 residing in Korea are required to be in possession of either their passport, an entrance permit for alien , or an Alien Registration Card. They must also produce one of these when asked by an Immigration official or other civil servant in the course of pursuing government business.

Re-Issuing of Alien Registration Card

Reasons for Re-Issuance
You can be issued another Alien Registration Card if you lose your current one, if it becomes damaged, or there is no room left to make needed amendments.
Period Within Which to Apply
You must apply within 14 days of having reason to apply.
Documentation to Prepare
Written explanation of reasons for application and one portrait picture.

Changing Status of Sojourn

Permissible Cases
This may happen when a foreign national ceases to engage in the activities permitted in his status of sojourn and then commence on activities requiring a different status of sojourn. If for example a foreigner has come to Korea on a short-term commercial visa but now wants to engage in investment activity or marry and live with a Korean national, he must receive permission for a change in status of sojourn. Unless there were unavoidable circumstances from the start, this is not permitted for persons initially having status under 90 days or who have entered the country with no visa.
Documentation to Prepare
Passport and Alien Registration Card, 50,000won for government revenue stamp , and documentation proving the new status of sojourn.
Things to Remember
The process usually takes around one week. As each status of sojourn classification requires different documentation, call Immigration before going to apply.

Extension on Period of Sojourn

Permissible Cases
Foreign nationals who seek to continue to stay in Korea beyond the period of sojourn of their current status of sojourn. You may apply for an extension starting from 30 days before the period of sojourn up until the date the period expires.
Documentation to Prepare
Passport, Alien Registration Card, 30,000won for government revenue stamp.
Things to Remember
The process takes about a week from the date you apply. The required documentation varies with status of sojourn, so call before going to the Immigration Office to apply.

Permit to Engage in Activity not Outlined in Status of Sojourn

When, for example, someone's flight departs after the date by which his period of sojourn expires, or if there are extenuating circumstances making him unable to leave within his period of sojourn, the person may be granted an extension lasting no more than 10 days. Documentation required will include items such as application form, air ticket, written description of the circumstances, etc.

Source: Korea Immigration