Telephone numbers in South Korea are organized and assigned using the following scheme.
International call out: 00N (where N is the carrier code) followed by the distant country code and telephone number.
Calling into Korea: +82 XX XXXX YYYY. The leading "0" is dropped when dialling into South Korea from overseas.
Some 1566/1577/1588 telephone numbers cannot be dialed from overseas.
Domestic long distance call: 0NN (where NN is the carrier code) followed by the 0XX area code and XXXX YYYY number. See Domestic long-distance service code and Area code.
Call to cellular : 01N XXXX YYYY (see Mobile phone number). When phone call is made between unified 010-number subscribers, leading 010 can be dropped (XXXX YYYY).
Special service call : 0N0 XXXX YYYY (see Special service)
For example;
Call 02-312-3456 within Seoul: 312-3456
Call 02-312-3456 from elsewhere: 02-312-3456
Call 051-212-3456 within Busan: 212-3456
Call 051-212-3456 from elsewhere: 051-212-3456
Call 02-312-3456 from abroad: +82-2-312-3456
South Korea uses an open dialing plan with a total length (including 0) of 9 to 11 digits and, within city, subscriber numbers 7 to 8 digits long. Dialing from mobile phones to any type of phone except 010 numbers, the area code must be included.
In 1998, telephone numbers in Seoul starting with 2 and 6 added more digit (02-2XX-YYYY to 02-22XX-YYYY, 02-6XX-YYYY to 02-26XX-YYYY). Before area codes were shortened from 4 digit to 2~3 digit in June 2000, there were 1 digit exchange number (usually "2") with some 2 digit exchange numbers so some phone numbers like 0347-61-XXXX, 0443-2-XXXX or 0525-40-XXXX existed. (now 031-761-XXXX, 043-652-XXXX and 055-340-XXXX)
001 - KT international call
002 - LG U+ international call
003xx - International call over Internet Protocol or international special services
00365 - Onse Telecom international call over Internet Protocol
005 - SK Broadband international call (Higher quality than the 5 digit prefix service from the same company)
006 - SK Telink international call (Higher quality than the 5 digit prefix service from the same company)
007xx - International call over Internet Protocol or international special services
00700 - SK Telink international call over Internet Protocol
00727 - KT international call over Internet Protocol
00766 - SK Broadband international call over Internet Protocol
00794 - Operator Service
008 - Onse Telecom international call (Higher quality than the 5 digit prefix service from the same company)
010 - Mobile (All South Korea Mobile Phone Companies, 2G, 3G and 4G from Jan 1, 2004)
011 - Mobile (SK Telecom, 2G until Dec 31, 2003)(All South Korea Mobile Phone Companies, 2G from Jan 1, 2004)
012 - Machine to machine (Former Beeper)
013xx - Mobile special net (wireless vessels etc.)
014xx - Point-to-Point Protocol Access number
015 - Mobile services: Paging services
016 - Mobile (KT, 2G until Jun 30, 2003)(All South Korea Mobile Phone Companies, 2G from Jul 1, 2004)
017 - Mobile (SK Telecom, 2G until Dec 31, 2003)(All South Korea Mobile Phone Companies, 2G from Jan 1, 2004)
018 - Mobile (KT, 2G until Jun 30, 2003)(All South Korea Mobile Phone Companies, 2G from Jul 1, 2004)
019 - Mobile (LG U+, 2G until Dec 31, 2004)(All South Korea Mobile Phone Companies, 2G from Jan 1, 2005)
030 - UMS
050 - Personal number service
060 - Telephone based intelligent service
070 - Internet phone (VoIP)
080 - Toll-free call
Before June 2000, South Korea used 2 to 4 digit area codes.
02 - Seoul and parts of Gyeonggi-do (Gwacheon, Gwangmyeong and some neighborhoods of Goyang and Hanam)
031 - Gyeonggi-do
032 - Incheon and parts of Gyeonggi-do (Bucheon and some insular communities of Ansan)
033 - Gangwon-do
041 - Chungcheongnam-do
042 - Daejeon and a part of Chungcheongnam-do (Gyeryong)
043 - Chungcheongbuk-do
044 - Sejong City
049 - Kaesong Industrial Region
051 - Busan
052 - Ulsan
053 - Daegu and a part of Gyeongsangbuk-do (Gyeongsan)
054 - Gyeongsangbuk-do
055 - Gyeongsangnam-do and a few neighborhoods of Ulsan
061 - Jeollanam-do
062 - Gwangju
063 - Jeollabuk-do
064 - Jeju-do
It is not necessary to dial any carrier prefix before making a domestic long-distance call. These prefixes are needed only when you want to choose a different carrier other than your default long-distance carrier (usually the same company that provides your phoneline).
081 - KT
082 - LG U+
083 - Onse Telecom
084 - SK Broadband
085xx - [Domestic long-distance Value Added Service (VAS)]
086 - SK Telink
087 - (Currently not in use)
088 - (Currently not in use)
100 - KT customer center
101 - LG U+ customer center
105 - Ship wireless service
106 - SK Broadband customer center
107 - LG U+ report
108 - SK Broadband business customer center
109 - KT report
111 - NIS
112 - Police
113 - Spy Reporting
Area Code + 114 - Directory assistance(Korea Info Service)
115 - KT Telegram
116 - KT standard time service
117 - School Violence Hotline (from 2012, previously: report sexual trafficking of women)
118 - Cyber terrorism report
119 - Fire brigade, ambulance
120 - Lifestyle service
121 - Water utility report
122 - Coast guard Emergency telephone number
123 - KEPCO Electric report
125 - Smuggling report
127 - Narcotics report
128 - Pollution report
129 - Coordination with social welfare service (after October 2005)
1300 - Postal services
1301 - Prosecutor service
Area Code + 131 - Weather forecasting
132 - Civil Action (Korea Legal Aid Corporation - for contract disputes)
1330 - KNTO tourist information (bus·train schedule, hotel·inn information, free translation service)
1331 - Human Rights Board
1332 - Finance Board
1333 - Transport information
1335 - Information communication service center
1336 - Infringement of personal information board
1337 - Military Safety Board
1338 - Communications service center and report
1339 - Emergency medical treatment
134 - Tourist information
1345 - Immigration Contact Center (Multilingual support)
1350 - Labor Board
1355 - National Pension Service
1357 - Small and medium enterprise support
1365 - Volunteering information
1366 - Domestic abuse report
1369 - Financial Information Inquiry
1377 - Foodbank
1379 - Unreasonable infringement of livelihood report
1382 - Citizen Registry Confirmation
1385 - Business discomfort report and board
1388 - Minor mistreatment report
1389 - Elderly abuse hotline and board
1390 - Election information and infringement hotline
1391 - Baby abuse hotline
1398 - Child abuse hotline
1399 - Unclean grocery report
141 - Contact room (KT)
182 - Missing child report hotline
188 - National Board of Audit and Inspection
082-17,1677 - uplus (Dacom) Collect call
1541 - KT Collect call
1677 - Onse Telecom Collect call
1682 - SK Telink Collect call
14XXXXXX
15XXXXXX
1544-XXXX - LG Dacom(LG U+) nationwide single number service
1566-XXXX - SK Broadband nationwide single number service
1577-XXXX - KT nationwide single number service
1588-XXXX - KT nationwide single number service
1599-XXXX - SK Telink nationwide single number service
16XXXXXX
1661-XXXX - LG U+ nationwide single number service
1688-XXXX - Onse Telecom nationwide single number service
