Decide which contact methods you need
List the people and accounts that use your existing number: family, accommodation, banks or airline accounts may contact you differently. Choose a setup that keeps the methods you actually need available.
An eSIM is a digital SIM profile. Some travel plans provide data only, while others include voice or SMS. A new Korean number does not receive messages sent to your home number unless a separate supported forwarding or account arrangement exists.
Check charges before leaving the home line active
Read your carrier's terms for incoming calls, outgoing calls, SMS, voicemail, data and Wi-Fi calling. A paid roaming session may start when you answer a call, send a message or use data, depending on the plan.
Turning off data roaming does not stop cellular voice calls or automatically prevent all charges. Check the default voice line and any automatic mobile-data switching on a dual-SIM phone.
If avoiding cellular roaming is essential, ask the carrier which settings or account restrictions achieve that while preserving the services you need.
Set up and test Wi-Fi calling
Enable supported Wi-Fi calling before departure and complete any required registration. Some carriers require activation while connected to the home network.
You can turn Wi-Fi back on after enabling airplane mode. On a supported device and carrier, Wi-Fi calling may then work over that connection. Confirm its status on the phone and test the arrangement; availability is not universal.
Wi-Fi calling is not automatically free. Check the destination-based charges in your plan. Verizon's guidance, for example, distinguishes calls back to the US from calls to other countries.
Keep account verification available
Where supported, prepare an authenticator, backup codes or another recovery method for important accounts. Test the new method before removing an existing one, and store recovery information securely.
If an account requires SMS to your home number, check how that line will receive messages in Korea. Receiving a code and receiving multimedia messages can have different carrier requirements and charges.
Korean subscriber-based identity verification is a separate service; a tourist plan with SMS does not necessarily support it.
Tell contacts how to reach you
Agree on a number or messaging service that you will check. KakaoTalk is a messaging app used by many Korean businesses, while your contacts may prefer another service.
Save essential phone numbers and booking details offline. Keep your phone charged and another way to ask for help if it fails. For an emergency in Korea, call 112 for police or 119 for fire, ambulance or rescue using an available connection.
