Korea eSIM Installed but No Internet on iPhone? Check Before Deleting It
Official guidance checked October 18, 2026 · Korea Standard Time
If your Korea travel eSIM appears under Settings → Cellular but mobile data is not working, first turn on that line and select it under Cellular Data. Then check the roaming and APN instructions for your specific plan. Do not delete the eSIM as a troubleshooting shortcut.
An installed profile, a working data connection and an app accepting your number are three different checks. Treating them as one “eSIM problem” can send you toward a fix that does not address the actual failure.
Start with the state you can actually see
- No new line appears: check device compatibility, carrier lock and the seller’s installation method.
- The line appears but is activating or has no service: check the product’s usable country, activation conditions and expiry.
- The line has a signal but no internet: check the selected data line, remaining allowance and the provider’s connection settings.
Do this over a trusted Wi-Fi connection or hotspot where possible, so the order details and support channel remain available.
In Korea, select the travel line for data
- Open Settings → Cellular and check the travel line is enabled.
- Open Cellular Data and select that travel line. The wording can differ with the device’s language or region.
- Follow the purchased plan’s instructions for Data Roaming and, if supplied, APN settings. Change the intended line, not both lines indiscriminately.
Apple’s roaming guide treats roaming as a line-specific setting. A local Korean product and an international travel product need not use identical settings. If the voucher gives no instruction, ask the provider rather than copying another brand’s APN.
Choosing the travel line for data does not make the home line’s calls or texts free. Keeping your usual number reachable is a separate roaming-cost decision. Check the home carrier’s Korea terms before leaving that line enabled.
If the line is missing or you have not arrived yet
For another carrier’s eSIM, Apple’s travel guidance says the iPhone must be unlocked. In Settings → General → About, look for “No SIM Restrictions” beside Carrier Lock. If it is locked, the existing carrier handles unlocking. Also check the model and country of purchase against Apple’s eSIM setup requirements and your seller’s supported-device list.
Purchase, installation and the start of paid use are not interchangeable. For a concrete local example, LG U+’s tourist data eSIM page says use starts with the first data usage and activation must occur within 60 days of purchase; its FAQ says the service works only in Korea. Check your actual voucher and current product terms rather than applying that timetable to another provider.
If it still fails, keep the profile and use support
Apple’s setup troubleshooting includes toggling Airplane Mode, switching the affected line off and back on, restarting, and checking carrier settings under General → About. Check the result after each step instead of changing several settings at once.
Apple warns against erasing an eSIM for troubleshooting unless the carrier directs it. LG U+ warns that a downloaded eSIM profile cannot be restored after deletion. Do not assume scanning the old QR code again will restore the service. Deleting a profile is not cancellation of a paid plan either.
A Korean number is not the same as identity verification
If internet works but a restaurant, taxi or banking service will not verify you, that may be a different problem. LG U+’s FAQ says its Data Only product does not support SMS verification. Its Voice/SMS service supports certain app-verification uses, such as restaurant or taxi services, but not banking or government identity verification. Acceptance still depends on the app’s requirements.
Before buying or changing plans for an app, check which verification the app actually requires. A working internet connection alone cannot answer that question.
Phone data works, but your laptop has no internet?
A working eSIM does not establish that your plan includes tethering. Check the exact purchased product's hotspot permission, separate allowance and any additional charges; a plan sold as unlimited phone data need not offer unlimited laptop use. Do not buy a top-up until the provider confirms what it changes.
For an iPhone, Apple says Personal Hotspot must be supported by the carrier and plan. Check Allow Others to Join and the current Wi-Fi password, then distinguish a missing network name from a password failure or a connected laptop with no internet. Keep the hotspot password enabled. Google's Android guidance also warns that some carriers restrict or charge for tethering; its settings are not iPhone instructions.
Check whether your plan restricts tethering before changing or deleting a working travel eSIM profile. The Korean hotspot troubleshooting guide separates those connection states in more detail. Hotspot guidance added on 21 October 2026; no individual carrier allowance or device connection was tested.
Considering a physical SIM instead?
KT’s visitor SIM page says the phone’s “country lock” must be off and warns that some models and frequency bands are unsupported. Check that condition with the carrier before choosing a physical SIM as an alternative.
Its two 90-day clocks differ: first use must be within 90 days of purchase; total service, extensions included, is limited to 90 days from initial activation. Voice/SMS needs an entry check at the airport KT roaming centre, while mobile-phone identity verification is not supported. These are this KT visitor product’s conditions, not common rules for all providers or long-term resident plans.
KT official SIM guide checked 22 October 2026; no purchase or activation test was performed.
What to send the provider
Use the seller’s official support channel with the order reference, exact error, iPhone model and purchase region, iOS version, whether you have arrived in Korea, and which line is selected for data. Keep the QR code, activation details, EID, IMEI and account information out of public posts. Follow the provider’s private support process for any identifiers it needs.
Prepared from the official guidance linked above; no purchase or activation test was performed. LG U+ conditions apply to that product, not every Korean eSIM. The related Korean-language article is retained. More practical guides are in Life in Korea.