What is a Phone Number Attached eSIM? Cases Where Calls and SMS are Necessary
The eSIMs available for overseas travel or business trips include not only data-only plans but also plans with a phone number.
A phone number attached eSIM allows you to use regular voice calls and SMS in addition to internet communication, provided you have a compatible plan.
If you only need app calls through LINE or WhatsApp, a data-only eSIM can suffice. However, if you want to call hotels or restaurants, need a local phone number, or want to receive SMS, a phone number attached eSIM is convenient.
This article clearly explains the mechanism of phone number attached eSIMs, their differences from data-only eSIMs, cases where calls and SMS are necessary, points to note for SMS authentication, and points to check before purchase.
Compatible plans can be found here
→ View compatible plans for phone number attached eSIMs
What is a Phone Number Attached eSIM?
A phone number attached eSIM is an eSIM that allows you to add a communication plan electronically to your smartphone and use a corresponding phone number for voice calls and SMS.
There is no need to swap out a physical SIM card; typically, you add it to your device using a QR code that you receive after purchase.
However, even if it is labeled as "phone number attached," the available features may vary depending on the plan.
- Plans that support both voice calls and SMS
- Plans that only support SMS reception
- Plans that only allow incoming calls
- Plans that support outgoing/incoming calls and SMS
- Plans that only allow phone numbers in specific countries
Therefore, it is important to check not just that there is a phone number, but also to confirm the extent of support for outgoing calls, incoming calls, SMS sending, and SMS receiving.
Differences from Data-Only eSIMs
eSIMs can be broadly categorized into data-only types and phone number attached types.
| Comparison Item | Data-Only eSIM | Phone Number Attached eSIM |
|---|---|---|
| Internet Communication | Available | Available depending on the plan |
| Regular Voice Calls | Not available | Available with compatible plans |
| SMS Reception | Not available | Available with compatible plans |
| SMS Sending | Not available | Available with compatible plans |
| LINE/WhatsApp Calls | Available | Available if data communication is supported |
| Regular Calls to Hotels/Stores | Not available | Available if voice call support is included |
| Fees | Relatively easy to choose | May include additional charges for calls and SMS |
If you only need to use maps, social media, web searches, and LINE calls, a data-only eSIM may be sufficient.
On the other hand, if you need to make regular calls or send SMS using a phone number, consider a phone number attached eSIM.
Cases Where a Phone Number Attached eSIM is Necessary
If You Want to Call Hotels or Restaurants
During overseas travel, there may be times when you need to call hotels or restaurants directly.
- Contacting the hotel about your arrival time
- Confirming shuttle services
- Making a reservation at a restaurant
- Changing reservation details
- Inquiring about lost items
If you need to contact facilities that do not support apps like LINE, a phone number attached eSIM that allows regular voice calls is convenient.
If You Need to Contact Local Guides or Business Partners
You may receive calls from local tour guides, drivers, or business partners.
Especially during overseas business trips, a regular phone number may be necessary for changes in meeting locations, confirming arrival times, or emergency contacts.
If You Are Receiving Deliveries of Luggage or Products
If you are using online shopping or food delivery during a long stay, you may receive calls or SMS from delivery personnel.
Some services require a local phone number for registration, so check which country's phone numbers are supported by the services you plan to use.
If You Want to Receive Regular SMS
Some phone number attached eSIMs have plans that support regular SMS reception.
If you may receive SMS from hotels, airlines, delivery services, or reservation services, check whether the plan supports SMS reception.
If You Are on an Overseas Business Trip or Long Stay
For short trips, app calls may be sufficient, but during overseas business trips or long stays, the need for a phone number increases.
- Contacting local companies
- Making reservations for business facilities
- Receiving deliveries or luggage
- Registering for local services
- Identity verification via phone or SMS
- Contacting your long-term accommodation
If your stay is long, it is also reassuring to check the validity period of the phone number, renewal methods, call fees, and SMS fees.
Can You Use SMS Authentication with a Phone Number Attached eSIM?
Even with a phone number attached eSIM, it does not guarantee that you can use it for all SMS authentication.
Whether SMS authentication can be used depends on the following conditions.
- Whether the plan supports SMS reception
- The country code of the assigned phone number
- Whether the service being authenticated accepts foreign numbers
- Whether prepaid numbers or virtual numbers are eligible for authentication
- Whether the service restricts specific carriers
For example, even if you can receive SMS with a phone number attached eSIM, services like banks, payment services, ride-hailing apps, and social media may not accept that number for authentication.
Therefore, if you are purchasing it for SMS authentication, it is important to confirm not only that it supports SMS reception but also whether you can register that number with the services you plan to use.
Especially for important authentications like banks or financial services, you may need the phone number you usually use in Japan.
Types of Calls Available with a Phone Number Attached eSIM
When choosing a phone number attached eSIM, check what types of calls are supported.
| Call/Communication Method | Requirements | Features |
|---|---|---|
| Regular Voice Calls | Phone number attached eSIM that supports voice calls | Can call phone numbers for hotels and stores |
| SMS | Plans that support SMS sending and receiving | Can receive short messages or authentication codes |
| LINE Calls | Data communication | Can call between LINE users |
| WhatsApp Calls | Data communication | Can call between WhatsApp users |
| App Calls (e.g., Messenger) | Data communication | Can call within supported apps |
If you want to call a hotel or store's landline, you need a plan that supports regular voice calls, not just LINE calls.
If you only need to contact family or friends, a combination of a data-only eSIM and app calls may suffice.
Who Should Consider a Phone Number Attached eSIM
- People who plan to call hotels or restaurants
- People who want to receive calls from local guides or business partners
- People who expect to receive SMS
- People using delivery services or food delivery
- People planning overseas business trips or long stays
- People for whom app calls alone are insufficient
- People using services that require a local phone number
On the other hand, if you only need to use maps, social media, web searches, LINE calls, or WhatsApp calls, a data-only eSIM may be easier to choose.
How to Choose a Phone Number Attached eSIM
Check the Country of the Assigned Phone Number
A phone number attached eSIM does not necessarily come with a phone number from the same country as your destination.
If the service you plan to use requires a specific country code, check which country's phone number will be assigned.
Check the Support for Outgoing and Incoming Calls
Even if there is a phone number, it may only support incoming calls or have limitations on outgoing calls.
Before purchasing, please check the following:
- Can you make outgoing calls?
- Can you receive incoming calls?
- Does it support domestic calls?
- Does it support international calls?
- Countries or regions where calls are possible
- Whether there is free call time
Check SMS Sending and Receiving
Even if it is labeled as SMS compatible, it may only support receiving.
If you plan to send SMS, check whether it supports both sending and receiving.
Check Data Capacity
Even with a phone number attached eSIM, there may be plans that do not include data capacity or only include voice calls and SMS.
If you plan to use maps, web searches, social media, or email, check whether data communication is included and how much capacity it has.
Check the Validity Period
Phone numbers and call balances may have a validity period.
Check that the phone number is valid from your arrival date to your return date, not just for your travel schedule.
Check Call and SMS Fees
With a phone number attached eSIM, call fees and SMS sending fees may be charged separately from the plan fee.
Since fees may vary depending on the destination or country, check the following costs:
- Initial costs
- Plan fees
- Domestic call fees
- International call fees
- SMS sending fees
- Additional charge fees
- Renewal fees
Check for Tethering Availability
If you plan to use a computer during an overseas business trip, check whether tethering is supported.
Even with a phone number attached plan, tethering may be restricted.
How to Set Up a Phone Number Attached eSIM
The basic setup method for a phone number attached eSIM is the same as for a data-only eSIM.
- Check if your smartphone supports eSIM
- Check if the SIM lock is removed
- Check the supported countries, calls, SMS, and data capacity
- Purchase a phone number attached eSIM
- Receive a QR code via email or other means
- Add the eSIM from your smartphone's settings
- Scan the QR code
- Turn on the eSIM line
- Set up mobile data communication and roaming
- Check the phone number, outgoing calls, incoming calls, and SMS
For detailed operation methods, please check the eSIM Setup Guide.
Check eSIM-Compatible Devices
Not all smartphones support eSIM.
Even with the same model name, eSIM may not be available depending on the country of sale, carrier, or model number.
Before purchasing, check the list of eSIM-compatible devices for your intended smartphone.
Set Up in a Stable Wi-Fi Environment
An internet connection is required to download the eSIM.
Setting it up in a stable Wi-Fi environment, such as at home before departure, will make the process smoother.
Do Not Accidentally Scan the QR Code with Another Device
The eSIM QR code may only be usable once.
Make sure not to confuse the device you are setting up, and do not delete the eSIM after installation.
Check the Phone Number After Setup
The phone number can sometimes be checked from the smartphone's line information or instructions received after purchase.
Before using outgoing calls or SMS, confirm the number, country code, and available features.
Points to Note When Using a Phone Number Attached eSIM
The Phone Number May Not Be a Local Number
The number assigned with a phone number attached eSIM may be from a different country than your travel destination.
If you are using services that require a local number, check the country code of the phone number before purchase.
Not All SMS Authentication is Supported
Even with a plan that allows SMS reception, the apps or services you use may not accept that phone number for authentication.
If you are purchasing it for SMS authentication, check the conditions of the services you plan to use.
May Not Support Emergency Calls
Travel or prepaid eSIMs may not support emergency calls to local police, fire, or medical services.
If you plan to use it for emergency contact, be sure to check the support details.
Call Fees May Be Charged Separately
Even with a plan that supports voice calls, call fees may not be included in the plan fee.
Check the call balance, free call time, and fees for each destination before use.
SMS Sending May Incur Fees
While receiving SMS may be free, sending may incur charges.
Check how many messages can be sent and whether additional fees are required.
Do Not Delete the eSIM During Your Trip
Once an eSIM is deleted, it may not be possible to reinstall it with the same QR code.
Even if you cannot use calls or SMS, do not delete it immediately; check the line settings and plan usage conditions first.
Cases Where a Data-Only eSIM Can Substitute
In the following cases, a phone number attached eSIM may not be necessary.
- Using Google Maps
- Conducting web searches
- Viewing and posting on social media
- Contacting via LINE or WhatsApp
- Using LINE calls or app calls
- Checking emails
- Watching videos
If you do not need to use a regular phone number or SMS, a data-only eSIM may offer easier plan options.
If you are looking for a data communication plan for travel to Japan, please check the Japan eSIM products and pricing plans.
Frequently Asked Questions About Phone Number Attached eSIMs
Can You Make Calls with a Phone Number Attached eSIM?
It is not guaranteed that you can make calls. Even with a phone number, the available features may be limited to SMS reception only or incoming calls only.
Check whether it supports both outgoing and incoming calls before purchasing.
Can You Use SMS Authentication with a Phone Number Attached eSIM?
Even if it supports SMS reception, it does not guarantee authentication with all services.
Check whether the apps or services you plan to use accept the assigned country phone number or prepaid number.
Can You Use LINE with a Phone Number Attached eSIM?
If the plan supports data communication, you can use LINE messages and calls.
However, for new registrations or phone number changes, check LINE's usage conditions.
What Country is the Phone Number From?
The country of the assigned phone number varies by plan. It is not guaranteed to be from the same country as your travel destination, so check the country code on the product page.
Can You Use a Phone Number Attached eSIM in Japan?
You may be able to use it if the plan includes Japan as a supported country.
However, whether a Japanese phone number is assigned or whether it supports domestic calls and SMS varies by plan.
Can You Tether with a Phone Number Attached eSIM?
Whether tethering is allowed depends on the plan and device. If you plan to connect a computer during an overseas business trip, check the support details before purchasing.
What Should You Do If Calls or SMS Are Not Working?
Check whether the eSIM line is turned on, whether you are within the usage period, whether the plan supports outgoing/incoming calls and SMS, and whether you have a balance.
If the issue persists, do not delete the eSIM; prepare your order number, device name, error screen, etc., and contact support.
Conclusion | Check the Supported Features if You Need Calls or SMS
A phone number attached eSIM is an eSIM that allows you to use regular voice calls and SMS in addition to data communication, provided you have a compatible plan.
It is suitable for the following people:
- People who want to make regular calls to hotels or restaurants
- People who want to receive calls from local guides or business partners
- People who want to receive SMS
- People who want to register a phone number with local services
- People planning overseas business trips or long stays
However, even if there is a phone number, it does not guarantee that you can use all features such as outgoing calls, incoming calls, SMS sending, and SMS receiving.
Additionally, even if SMS reception is supported, it does not guarantee that SMS authentication can be used with all apps and services, so checking before purchase is important.
Compare the country of the phone number, call support, SMS support, data capacity, fees, and validity period, and choose a plan that fits your usage purpose.
View compatible plans for phone number attached eSIMs
