Compatibility comes before price
A travel eSIM is useful only when the device supports eSIM and the carrier has unlocked it for another provider. Apple tells travellers to check Carrier Lock for ‘No SIM Restrictions’; Google likewise says a Pixel must be SIM-unlocked to use another carrier. Confirm this before buying because activation failure is not a Korea coverage problem.
Data-only and local-number plans solve different jobs
Many travel eSIM offers are data-only. Maps, messaging and app-based calls may work well on data, but a service that explicitly requires a Korean voice number needs a plan that includes one. Do not assume every eSIM includes calls or SMS: read the exact live product description.
Setup and fallback
Install before departure while reliable Wi-Fi is available, save the activation instructions offline and keep the home line from using costly data roaming. A physical SIM remains practical for a compatible unlocked phone without eSIM support. Keep the booking QR code private because it can control activation.