Even after installing the eSIM, you may encounter issues such as "unable to connect to the internet," "signal is displayed but cannot communicate," or "eSIM not working after arriving overseas."
The reasons for eSIM connectivity issues often lie in the smartphone settings, such as the selection of the eSIM line, data roaming, APN settings, start date of use, and supported areas.
By checking the settings in order from the top, you may be able to resolve the issue before contacting support.
This article will clearly explain the points to check when the eSIM is not connecting and specific solutions, including APN settings, for both iPhone and Android.
If you are using eSIM for the first time, please also check the eSIM setup guide first.
Main Causes of eSIM Connectivity Issues
When the eSIM cannot communicate, the following causes are primarily considered.
| Main Cause | Points to Check |
|---|---|
| eSIM line is OFF | Enable the eSIM line you want to use |
| Different mobile data communication line | Select the eSIM for data communication |
| Data roaming is OFF | Turn ON roaming for the travel eSIM |
| Incorrect APN settings | Check the APN provided after purchase |
| Before start date or expired | Check the start conditions and usage period |
| Out of supported area | Check the target countries/regions of the purchased plan |
| Data capacity exhausted | Check remaining data capacity and communication limits |
| Device does not support eSIM | Check the compatible models and SIM lock status |
One common issue is that the eSIM has been added to the device but is not selected as the line for mobile data communication.
For overseas eSIMs, you may not be able to communicate unless data roaming is turned ON.
Order of Checks When eSIM is Not Connecting
When unable to communicate, instead of changing the settings repeatedly, check in the following order.
- Check the start date and supported countries
- Turn ON the eSIM line
- Select the eSIM for mobile data communication
- Turn ON data roaming
- Check the APN settings
- Toggle airplane mode ON and OFF
- Restart the smartphone
- Check the network selection
- Check the data capacity
- Check the compatible device and SIM lock
If communication is restored at any point, there is no need to change the subsequent settings.
Also, avoid deleting the eSIM immediately just because you cannot connect. If the QR code can only be used once, you may not be able to reinstall it.
1. Check the Start Date and Supported Countries
First, confirm whether the purchased eSIM can be used in the current country of stay and whether the usage period has started.
The timing for starting to use the eSIM varies by product.
- Starts when connected to the local communication network
- Starts when the eSIM is installed
- Starts from the date specified at the time of purchase
- Starts a certain period after the QR code is issued
If it is before the start date or after the expiration date, you will not be able to communicate even if the settings are correct.
Additionally, country-specific eSIMs can only be used in the specified countries. Even with a travel plan, not all countries may be covered.
When using in Japan, you can check the supported days and data capacity from the Japan eSIM product and pricing plans.
If you want to know more about how to choose an eSIM for traveling in Japan, please refer to the Complete Guide to Japan eSIM.
2. Check if the eSIM Line is ON
Even if you have installed the eSIM, you cannot communicate if the line is still OFF.
How to Turn ON the eSIM Line on iPhone
- Open "Settings"
- Select "Cellular"
- Select the eSIM you want to use
- Turn ON "Turn On This Line"
If you have registered multiple SIMs or eSIMs, be careful not to confuse your regular line with the travel eSIM.
How to Turn ON the eSIM Line on Android
- Open "Settings"
- Select "Network & Internet" or "Connections"
- Select "SIM" or "SIM Manager"
- Turn ON the eSIM you want to use
On Android, the names of the settings may vary depending on the manufacturer and model, such as Google Pixel, Samsung Galaxy, AQUOS, etc.
3. Select the eSIM for Mobile Data Communication
Even if the eSIM line is ON, if a different SIM is set for mobile data communication, you will not be able to communicate with the purchased eSIM.
For iPhone
- Open "Settings"
- Select "Cellular"
- Select "Cellular Data"
- Select the travel eSIM
If "Allow Cellular Data Switching" is ON, the device may automatically switch to a different line.
To avoid incurring unintended overseas roaming charges on your regular SIM, turn it OFF if necessary.
For Android
- Open "Settings"
- Select "SIM" or "SIM Manager"
- Select "Mobile Data"
- Specify the travel eSIM
On devices that allow separate settings for voice SIM and data SIM, set the travel eSIM for mobile data.
4. Turn ON Data Roaming
Many eSIMs for overseas travel connect to the local carrier's network via roaming.
Therefore, if data roaming is OFF for the relevant eSIM line, you may not be able to connect to the internet even if the signal is displayed.
How to Turn ON Data Roaming on iPhone
- Open "Settings"
- Select "Cellular"
- Select the eSIM you want to use
- Turn ON "Data Roaming"
How to Turn ON Data Roaming on Android
- Open "Settings"
- Select "Network & Internet" or "Connections"
- Select the eSIM you want to use
- Turn ON "Roaming"
Please turn ON data roaming on the purchased travel eSIM.
If you turn ON data roaming on your regular line, you may incur overseas roaming charges from your contracted carrier.
5. Check the APN Settings
Depending on the eSIM, APN settings may be required after installation.
APN stands for "Access Point Name," which is the configuration information needed to connect your smartphone to the carrier's network.
If the APN is not entered or is incorrect, you may not be able to connect to the internet even if the signal or 4G/LTE/5G is displayed.
Symptoms that May Indicate APN Settings Issues
- Signal is present but cannot open websites
- 4G/LTE/5G is displayed but cannot communicate
- Cannot connect even with data roaming ON
- No improvement after toggling airplane mode or restarting
- Only some apps cannot communicate
Items to Check in APN Settings
- APN name
- Username
- Password
- Authentication type
- APN type
The required settings may vary depending on the eSIM product and carrier.
If the APN information is included in the purchase confirmation email or setup instructions, please enter it accurately, including uppercase and lowercase letters, symbols, and spaces.
How to Check APN Settings on iPhone
On iPhone, the APN may be automatically configured when you add the eSIM.
If manual entry is required, check the following items.
"Settings"
→ "Cellular"
→ Select the eSIM
→ "Cellular Data Network"
If "Cellular Data Network" is not displayed, it may not be possible to change it manually due to the device or carrier specifications.
How to Check APN Settings on Android
On Android, you can generally check it in the following flow.
"Settings"
→ "Network & Internet" or "Connections"
→ "Mobile Network"
→ "Access Point Names" or "APN"
If you add a new APN, save it after entering the information and select the created APN.
Simply saving may not activate the new APN.
6. Toggle Airplane Mode ON and OFF
If the smartphone is not able to properly acquire the local communication network, toggling airplane mode may help.
- Turn ON airplane mode
- Wait for about 10 to 30 seconds
- Turn OFF airplane mode
- Check the signal or 4G/5G display
Toggling airplane mode allows the smartphone to rescan for available networks.
This is an effective measure right after arriving at the airport or after moving between multiple countries.
7. Restart the Smartphone
After changing the eSIM or APN settings, it is recommended to restart the smartphone.
In particular, it is advisable to restart after performing the following actions.
- After adding the eSIM
- After turning ON the eSIM line
- After changing the APN settings
- After switching the mobile data line
- After changing the network selection
Restarting may help ensure that the changed communication settings are correctly applied.
8. Check the Network Selection
Typically, smartphones automatically select the available carriers.
If automatic selection does not connect to the correct network, manually selecting the carrier may help.
For iPhone
"Settings"
→ "Cellular"
→ Select the eSIM
→ "Network Selection"
Initially, set "Automatic" to ON and check.
If you still cannot communicate, turn OFF "Automatic" and select the carrier listed in the post-purchase instructions.
For Android
"Settings"
→ "Network & Internet" or "Connections"
→ "Mobile Network"
→ "Automatically select network"
If you are manually selecting, make sure to choose a carrier that is compatible with the eSIM you are using.
9. Check if Data Capacity is Exhausted
With eSIMs that have data limits, you may be unable to communicate or experience significantly reduced speeds once the data capacity is exhausted.
Please check the following items.
- Remaining data capacity
- Daily high-speed communication limit
- Conditions for speed restrictions
- Usage period
- Possibility of purchasing additional data
Streaming videos, video calls, tethering, and backing up photos and videos consume a lot of data capacity.
If you are unsure about the required capacity, please check the estimated data usage.
If you want to compare plans that suit your travel days and purposes in Japan, the comparison of Japan eSIM pricing and plans is also helpful.
10. Check eSIM-Compatible Devices and SIM Lock
To use eSIM, your smartphone must be compatible with eSIM.
Additionally, even if the device is eSIM-compatible, if it is SIM locked, you may not be able to use eSIMs from other carriers.
Points to Check
- Is the device you are using eSIM-compatible?
- Is the country of sale and model number compatible with eSIM?
- Is the SIM lock removed?
- Is the device's OS up to date?
- Is it compatible with the communication frequencies of the country of use?
Even with the same model name, specifications may differ depending on the country of sale and carrier.
Please check the list of eSIM-compatible devices before purchasing.
Checklist for iPhone When eSIM is Not Connecting
- "Turn On This Line" is set to ON
- The travel eSIM is selected for mobile data communication
- Data roaming for the travel eSIM is set to ON
- Data roaming for the main line is set to OFF
- Network selection is set to automatic
- APN information is entered correctly
- Tried toggling airplane mode ON and OFF
- Restarted the device
If you have registered multiple lines, be careful not to confuse the settings for your main line and the travel eSIM.
Checklist for Android When eSIM is Not Connecting
- The travel eSIM is enabled
- The travel eSIM is specified for mobile data communication
- Data roaming for the travel eSIM is set to ON
- APN is saved and selected correctly
- Preferred network is set to 4G/5G
- Network automatic selection is set to ON
- Tried toggling airplane mode ON and OFF
- Restarted the device
Android settings screens may differ by manufacturer and OS, so if you cannot find the settings, please check the manufacturer's instructions.
Things to Check Before Deleting eSIM
It is not recommended to delete the eSIM profile immediately just because it is not connecting.
The eSIM QR code may only be usable once.
If you scan the same QR code after deletion, you may not be able to reinstall it, and you may need to reissue the QR code.
Before deleting, please check all of the following.
- eSIM line ON/OFF
- Selection of mobile data communication
- Data roaming
- APN settings
- Toggle airplane mode
- Restart the device
- Start date and usage period
- Supported countries/regions
If you cannot resolve the issue yourself, please contact support before deleting the eSIM.
Information to Prepare Before Inquiry
If you cannot communicate even after checking the settings, please contact support.
Having the following information ready will help expedite the identification of the cause.
- Order number
- Name of the purchased eSIM product
- Current country/region of stay
- Smartphone model name
- OS version
- eSIM line settings screen
- Mobile data communication selection screen
- Data roaming settings screen
- APN settings screen
- Displayed error messages
- Presence of signal or 4G/5G display
Having screenshots of the settings screens will make it easier to convey the situation accurately.
However, be careful not to include personal information such as QR codes, phone numbers, or email addresses in the screenshots.
If you would like to consult about the setup or connection of the Japan eSIM, please check the Japan eSIM setup and support information.
If you cannot connect after arriving in Japan, detailed confirmation procedures are also provided in the troubleshooting guide for Japan eSIM.
Things to Prepare Before Traveling Overseas
If the eSIM does not connect after arriving overseas, it may be difficult to resolve the issue due to a lack of internet access to research the setup methods.
It is reassuring to prepare the following before departure.
- Check if the device is eSIM-compatible
- Check if the SIM lock is removed
- Check the eSIM setup method
- Save the post-purchase setup instructions
- Save a screenshot of the APN information
- Check the start conditions for use
- Check the countries and communication areas
- Check how to contact support
However, depending on the product, the usage period may start from the time the eSIM is installed.
When setting up before departure, be sure to check the usage conditions of the purchased product.
Frequently Asked Questions When eSIM is Not Connecting
Q1. The signal is present, but I cannot connect to the internet.
Please check if the travel eSIM is selected for mobile data communication and if data roaming is set to ON.
If there is no improvement, check the APN settings, usage period, and remaining data capacity.
Q2. Why can't I communicate even though 4G or 5G is displayed?
Even if you are receiving a signal, you may not be able to communicate if the APN is not set correctly or if you have exhausted your data capacity.
Please check the APN information, usage period, and conditions for communication limits.
Q3. Is APN setting always necessary?
It is not required for all eSIMs.
Some eSIMs automatically set the APN. Only follow the instructions to set it if the APN information is included in the post-purchase instructions.
Q4. Is it okay to turn ON data roaming?
For overseas eSIMs, it may be necessary to turn ON data roaming.
Make sure to turn it ON for the travel eSIM and avoid unnecessary overseas roaming charges on your regular line.
Q5. Will deleting and reinstalling the eSIM improve the situation?
It does not guarantee improvement.
If the QR code can only be used once, you may not be able to reinstall it after deletion. It is recommended not to delete it before confirming with support.
Q6. What should I do if the Japan eSIM is not connecting?
Please check the eSIM line, mobile data communication, data roaming, APN settings, and start date.
For detailed confirmation methods, please refer to the troubleshooting guide for Japan eSIM.
Q7. Do I need the same settings for eSIM with a phone number?
Even for eSIMs with a phone number, basic settings are required for data communication.
However, the conditions for using voice calls and SMS may vary by product. For details, please check eSIM with a phone number.
Q8. What could be the reason for slow communication even if there are no issues with the settings?
Possible reasons include the signal conditions in the area, peak times, usage in basements or buildings, and communication speed restrictions.
Please try moving to a different location, toggling airplane mode, or checking the remaining data capacity.
For other questions, please also refer to the frequently asked questions about eSIM.
Conclusion | Check Settings in Order When eSIM is Not Connecting
Even if the eSIM is not connecting, it does not necessarily mean that the device is faulty or that there is an issue with the eSIM itself.
In many cases, you can improve the situation by checking the following settings in order.
- Check the start date and supported countries
- Turn ON the eSIM line
- Select the travel eSIM for mobile data communication
- Turn ON data roaming
- Check the APN settings
- Try toggling airplane mode ON and OFF
- Restart the smartphone
- Check the network selection
- Check the data capacity
- Check the eSIM-compatible device and SIM lock
Especially for overseas travel eSIMs, the selection of the mobile data communication line, data roaming, and APN settings are crucial.
If you cannot connect, do not delete the eSIM immediately; check the settings screen first and then contact support.
If you are planning to purchase an eSIM for traveling in Japan, please check the Japan eSIM product and pricing plans.
If you want to compare prices, days, and data capacity, the comparison of Japan eSIM pricing and plans is also helpful.
