Basic Information on Cell Phones:
SK, KT, and LG are the three major cell phone service providers in Korea. They all offer a prepaid plan (선불 - 'seonbul') and a regular contract (후불 - 'whobul'). If you decide to get a regular contract, the service provider may require you to put down a security deposit. This is because foreigners usually do not have an established credit record or history in Korea and they want to protect themselves in case the foreign customer decides to leave the country without paying the bills. Again, most major carriers have English service lines, and many service carriers have special plans for foreigners as well.