There are two ways to get a mobile phone in Korea. You can either buy a secondhand prepaid phone in one of the many designated stores, or you can get a prepaid SIM-card to use in your own (SIM-lock free) phone. In Korea only 3G and 4G (LTE) networks are being used; so keep in mind that if you bring your own phone, that it should support one of these network types.
During the orientation at the start of each semester you will be able to buy a SIM-card.
Prepaid phone
When you bought a (secondhand) prepaid phone, you need to activate it at one of the telecom stores. Not all phones are compatible with all telecom providers. So inform to what telecom provider you need to go when you bought the phone.
Prepaid SIM-card
When you buy a prepaid SIM-card to use in your (smart)phone. You will be able to connect to one of the free Wi-Fi networks as well. Most providers have Wi-Fi hotspots everywhere through Seoul, you will only be able to connect to the network if you have a SIM-card of that specific provider.
Activation
When you bought your phone or SIM-card, you will need to activate this at a telecom store of the provider. In most cases the telecom provider requires you to have an Alien Registration Card in order to register and activate the phone or SIM-card. However, in some cases they also accept your (foreign) passport for registration and activation.
Subway phones
In case you don’t have a mobile phone, you can use the free subway phones which are located on every subway station. You can call for 60 seconds for free to any number in Korea. If you need to call longer, you can use your T-money card.