Korea has very advanced communication systems and Internet facilities. People can use the Internet, telephone and even mobile phones everywhere.

Telephones

If you want to install a new telephone or have problems with it, you can dial "100" everywhere in the country. Telephone bills can be paid at banks or by automatic withdrawal from your bank account.

Many foreigners buy prepaid telephone cards or use prepaid phones. Foreigners need to have an alien registration card in order to purchase a mobile phone in Korea.

Mobile phones

Buying a mobile phone isn't easy for non-Koreans. He or she must have an Alien Registration Card with them and must pay for the phone with cash. For this reason, most foreign nationals rent a mobile phone and use a prepaid phone card, which can be used by entering the card number into the mobile phone, allowing them to use the balance on the card. Although there isn't any subscription fee or other charges, calls are a bit more expensive. 

Internet phones

Internet phones can be used to make phone calls online to computers or telephones. They are especially inexpensive for overseas calls. They may be ordered from the local cable or telecommunications company such as KT, SK broadband, LG U+ or over the Internet. 

Cable TV and Internet

Korea has three major terrestrial TV stations-KBS, MBC and SBS-as well as cable TV, local cable broadcasting relay operators, and satellite TV (Sky Life). More recently, Internet-based IPTV has also become available. If you just want Internet, you will have to contact one of the Internet communication companies, which charge different fees. You can also access the Internet at nearby PC rooms.

Useful Tips

Pay phones

Pay Phones

When you use pay phones on the street, you need to insert coins or a telephone card. You can purchase pay phone cards at convenience stores or supermarkets.

Emergency Calls

All pay phones have a red button for emergency calls. Press the red button to report crime and fire or for emergency assistance. Coins are not needed. Push the red button (emergency call) +112 to report a crime, or push the red button + 119 for fire, rescue or other emergencies.

Collect Calls

Those who don't have a pay phone card or coins can charge a call to the receiving party. Fees are slightly higher than normal calls. You can use this service by pushing the red button +1541 + phone number + #.

[Source: Korea.net]