List the tasks before choosing the product. Maps and messaging need data; a local call, incoming text or identity check may require something different. A local-looking number is not a universal login solution.
Compare the practical constraints
| Option | Check first | Everyday tradeoff |
|---|---|---|
| eSIM | Exact handset/variant, unlocked status and product compatibility | Installation and activation rules matter; do not assume it can be reinstalled |
| Physical SIM | Unlocked compatible phone and collection/activation requirements | Keep your original SIM safe and understand how you will receive home-number messages |
| Pocket Wi-Fi | Battery, connected-device limits, collection/return and coverage | The group may need to stay near the device; plan charging and return |
These are editorial tradeoffs, not a guarantee for every device, country variant or provider.
Read the exact product's calls and texts
KT's tourist eSIM page distinguishes data from voice/outgoing-SMS products and conditions some services on entry verification and matching passport information. Do not generalize “data-only means no incoming SMS” across all products.
KT also explicitly says its tourist eSIM does not support Korean personal authentication. Receiving a text or having an 010 number does not establish acceptance by a bank, ticketing service or app that requires local identity verification.
Resolve installation uncertainty before paying
The checked KT page contains a 90-day heading and a conflicting 30-day installation caution. We do not present either as a verified universal deadline. Ask for the exact current terms of the product you intend to buy, including installation, activation, expiry and support.
Follow the selected provider's instructions. KT's one-install/no-delete warning is product-specific; do not delete an installed eSIM as a guessed troubleshooting step.
Keep arrival usable if activation fails
Save the hotel address and map routine, arrival instructions and support channel before flying. Have a way to contact the provider and an independent payment method; do not assume the same phone connection will solve every failure.
For a group, decide who needs an independent connection if you split up. Check the airport-to-hotel route before arrival so the first transport decision does not depend on a hurried product purchase.