The difference between LINE calls and eSIMs with phone numbers | Which is necessary for overseas travel?

Many people may be wondering whether to use LINE calls or prepare a phone number with an eSIM as a means of communication while traveling abroad.

LINE calls are a feature that allows LINE users to make calls to each other using an internet connection.

On the other hand, a phone number with an eSIM is a communication plan that allows you to make and receive calls using a regular phone app with the assigned phone number.

If your main communication is with family and friends, you can manage with a data-only eSIM combined with LINE calls.

However, if you want to make regular phone calls to hotels, restaurants, hospitals, airlines, etc., you may need a phone number with an eSIM that supports voice calls.

Additionally, since LINE calls cannot receive regular SMS, if SMS authentication is required, you will need to prepare your usual SIM or a phone number with an eSIM that supports SMS.

In this article, we will clearly explain the differences between LINE calls and phone numbers with eSIMs, their costs, who you can call, how they handle SMS authentication, and which one you should choose for overseas travel.

Differences Between LINE Calls and Phone Numbers with eSIM

The main difference between LINE calls and phone numbers with eSIMs is the mechanism used for calls and the people you can call.

What is LINE Call?

LINE call is a feature that allows voice and video calls through the LINE app.

Since it uses an internet connection rather than a phone line, it can be used overseas as long as you have data connectivity.

Even with a travel data-only eSIM, you can use LINE calls as long as you are logged into the LINE app.

What You Can Do with LINE Calls

• Voice calls between LINE users
• Video calls between LINE users
• Group calls with multiple participants
• Sending messages and photos
• Sharing location information

What You Cannot Do with LINE Calls

• Make regular calls to people who do not use LINE
• Make regular calls to fixed phone numbers of hotels or restaurants
• Receive calls on a regular phone number
• Send or receive regular SMS
• Use SMS authentication with a phone number

If your family and friends use LINE, you can communicate using only LINE calls.

On the other hand, if you need to call facilities or businesses at your travel destination, you may need a regular phone number.

What is a Phone Number with eSIM?

A phone number with an eSIM is an eSIM that allows you to use a phone number in addition to data communication.

The supported features vary by product.

• Making and receiving voice calls
• Receiving SMS
• Sending SMS
• Mobile data communication

However, just because it is labeled "with phone number" does not mean that all features are available.

Even if a phone number is assigned, some products may not support voice calls and only allow SMS reception.

For information on plans with phone numbers, please see Phone Number with eSIM.

Do You Need a Phone Number with eSIM for LINE Calls?

If you are only using LINE calls, you do not need a phone number with an eSIM.

As long as you have a data-only eSIM that can connect to the internet, you can use LINE calls.

Here’s what you need while traveling:

• eSIM-compatible smartphone
• Available data connection
• Configured LINE app
• LINE account of the person you want to contact

For data communication plans for traveling to Japan, please check Japan eSIM Products and Pricing Plans.

When You Might Need a Phone Number with eSIM

Calling Hotels or Inns

You may need to make regular phone calls to hotels to change your arrival time, report a late check-in, request a shuttle, or inquire about forgotten items.

If you cannot contact them through the reservation site’s messaging or email, a voice call-compatible phone number with an eSIM is convenient.

Making Reservations or Changes at Restaurants

Some restaurants in Japan do not support online reservations or English messaging.

If you need to communicate changes or cancellations to your reservation by phone, a regular phone call is necessary.

Contacting Hospitals or Insurance Companies

If you fall ill during your trip, you may need to call hospitals, travel insurance companies, or support centers.

Inquiring with Airlines or Transportation Services

You may need to call regarding flight changes, cancellations, lost luggage, or forgotten items on trains.

Receiving Calls from Delivery Services

When receiving packages or deliveries, you may receive calls or SMS from delivery personnel.

Registering a Japanese Phone Number as a Contact

For business trips, studying abroad, part-time jobs, or long-term stays, you may be asked to provide a Japanese phone number as a contact.

When LINE Calls Are Sufficient

• Mainly communicating with family and friends
• All travel members use LINE
• Contacting hotels through the reservation site
• Not using regular phone calls to stores
• No need to register a Japanese phone number
• Receiving SMS authentication on your usual SIM
• Short-term sightseeing trips

In general sightseeing trips, a combination of a data-only eSIM and LINE calls can often suffice.

Comparing Costs of LINE Calls and Phone Numbers with eSIM

LINE calls typically do not incur per-minute call charges.

However, voice and video calls will consume data.

With a phone number with an eSIM, in addition to plan fees, there may be charges for voice calls and SMS sending.

If you want to compare costs, please also check Japan eSIM Pricing and Plan Comparison.

How Much Data Does LINE Call Use?

LINE calls use data, so the amount of data consumed will depend on the call duration.

The actual data usage varies depending on the communication environment, sound quality, device, and app condition.

If you plan to have long video calls, choose a plan with sufficient data capacity.

For data usage estimates by purpose, please see Data Usage Estimates.

Differences in Call Quality

LINE Calls

The quality of LINE calls is affected by the speed and stability of the internet connection.

In areas with weak signals or congested networks, the audio may cut out or experience delays.

Voice Calls with Phone Number with eSIM

Plans that use regular voice lines operate differently from app-based calls that use data communication.

However, call quality may vary depending on the network connection status of the eSIM and the coverage area.

What to Do If the Other Person Does Not Use LINE?

If the other person does not use LINE, you cannot contact them via LINE calls.

Consider the following options:

• Make a regular call from a phone number with an eSIM
• Use international roaming calls with your usual SIM
• Borrow a hotel phone
• Use the messaging feature on the reservation site
• Inquire via email
• Request assistance from local staff or travel support

Making calls from your usual SIM may incur international roaming charges.

Can You Call Hotels or Stores with LINE Calls?

With regular LINE calls, you will be calling someone who has a LINE account.

You generally cannot directly call fixed phone numbers of hotels or stores from regular LINE calls.

If you plan to call hotels or stores, prepare the following options:

• Voice call-compatible phone number with eSIM
• Main line that supports international roaming
• Public phone at hotels or airports
• Official chat or inquiry form of the facility

LINE Calls Cannot Receive SMS Authentication

LINE calls and regular SMS are separate services.

Even if you can use LINE calls, you cannot receive regular SMS authentication codes sent from banks, credit cards, ride-hailing apps, etc.

If you want to receive SMS authentication while abroad, consider the following methods:

• Keep your usual SIM for SMS reception
• Use a phone number with an eSIM that supports SMS reception
• Use email authentication
• Pre-configure an authentication app
• Save backup codes

Even if you can receive SMS with a phone number with an eSIM, it does not guarantee that all services will accept SMS authentication.

Short-term numbers or prepaid numbers may be excluded from authentication eligibility.

How to Use Your Usual SIM and Data-Only eSIM Together

If you have a dual SIM-compatible device, you can keep your usual SIM for phone number and SMS use while using the travel eSIM for data communication.

With this setting, you can use the travel eSIM for LINE calls and internet, while still being able to receive SMS authentication codes sent to your usual phone number.

However, there may be international roaming charges for voice calls and SMS sent from the main line.

Which One Do You Need for Overseas Travel?

Short-Term Sightseeing Trips

If your main activities are communicating with family and friends, using maps, translations, and social media, you can manage with a combination of a data-only eSIM and LINE calls.

If You Want to Call Hotels or Restaurants

If you need to call hotels or stores that do not use LINE, a voice call-compatible phone number with an eSIM is convenient.

Business Trips to Japan

If you need to make regular calls to clients or accommodations, a phone number with an eSIM is suitable.

If you are communicating via Teams, Slack, Zoom, etc., a data-only eSIM can also suffice.

Studying Abroad or Long-Term Stays

If you need to register a phone number with schools, workplaces, real estate companies, or delivery services, consider a plan with a Japanese phone number.

If SMS Authentication is Required

You cannot receive SMS with LINE calls.

You will need to maintain your usual SIM or have a phone number with an eSIM that supports SMS.

Recommendations by Purpose of Use

Advantages of LINE Calls

• Generally free for calls between LINE users
• Can be used with a data-only eSIM
• Can choose between voice and video calls
• Group calls are possible
• Can also share messages and location information
• Easier to keep costs down compared to plans with phone numbers

Disadvantages of LINE Calls

• The other person must also use LINE
• Generally cannot call hotel or store phone numbers
• Audio may become unstable in poor communication conditions
• Cannot receive regular SMS
• Cannot make emergency calls

Advantages of Phone Numbers with eSIM

• Can make calls to regular phone numbers
• Can receive calls on the assigned number
• Can call hotels and restaurants
• There are plans that allow SMS reception
• Can sometimes be registered as a Japanese contact
• Can contact people who do not use LINE

Disadvantages of Phone Numbers with eSIM

• Tends to be more expensive than data-only eSIMs
• May require identity verification
• May incur additional charges for call and SMS sending
• May have an expiration date for the phone number
• Not all SMS authentication may be supported
• Short-term plans may not allow you to keep the same number

Points to Check Before Traveling Abroad

• Is the contact person using LINE?
• Do you plan to make regular phone calls to hotels or stores?
• Do you need to receive calls during your trip?
• Is there a possibility of using SMS authentication?
• Can you maintain your usual SIM while abroad?
• Travel duration and required data capacity
• Do you have enough data capacity for LINE calls?
• Call and SMS charges for phone number with eSIM
• Is your device compatible with dual SIM?

For information about compatible devices, please check List of eSIM-Compatible Devices.

What to Do If You Cannot Use LINE Calls Abroad

• Check if the travel eSIM line is ON
• Select the travel eSIM for mobile data
• Set data roaming according to product instructions
• Toggle airplane mode ON and OFF
• Restart the device
• Allow the LINE app to use mobile data
• Check communication speed and remaining data
• Connect to a stable Wi-Fi network

For detailed setup instructions for eSIM, please see eSIM Setup Guide.

If you cannot connect, please also refer to Troubleshooting Japan eSIM Connectivity Issues.

Frequently Asked Questions About LINE Calls and Phone Numbers with eSIM

Can I use LINE calls abroad?

Yes, as long as you can connect to the internet, you can use it abroad.

Can I use LINE calls with a data-only eSIM?

Yes, you can. LINE calls use data communication, so a regular phone number is not required.

Can I call hotels from LINE calls?

Generally, you cannot call fixed phone numbers of hotels from regular LINE calls.

Are there charges for LINE calls?

Calls between LINE users are generally free, but they consume data.

Can I receive SMS authentication with LINE calls?

No, you cannot. Regular SMS authentication requires a SIM or eSIM that can receive SMS.

Can I always receive SMS authentication with a phone number with eSIM?

It is not guaranteed. Some authentication services may restrict short-term or prepaid numbers.

Can I always make regular calls with a phone number with eSIM?

It is not guaranteed. Please check if it supports making and receiving voice calls.

Is a phone number with eSIM necessary for short trips?

If your main communication is with family and friends via LINE, and you are using maps and social media, a data-only eSIM will suffice.

Can I use LINE calls while keeping my usual phone number?

If you have a dual SIM-compatible device, you can keep your usual line for SMS and use the travel eSIM for LINE call data.

Can I use LINE calls for emergency calls?

No, it cannot be used as a regular emergency call method.

Please check the methods of contact and available phone lines in case of emergencies in advance.

What causes LINE calls to drop?

Possible causes include weak signals, network congestion, speed restrictions, or running out of data capacity.

Which is cheaper?

Generally, a combination of a data-only eSIM and LINE calls tends to be more cost-effective.

Phone number plans may be more expensive due to the inclusion of voice call and SMS features.

For inquiries about purchases or setup, please see Japan eSIM Support.

For other questions, please check Frequently Asked Questions about eSIM.

Conclusion: If You Don't Need Regular Calls or SMS, LINE Calls Can Suffice

LINE calls utilize an internet connection, so they can be used with a data-only eSIM.

If your main communication is with family and friends who also use LINE, you may not need to prepare a phone number with an eSIM.

On the other hand, consider a phone number with an eSIM in the following cases:

• If you want to make regular calls to hotels or restaurants
• If you want to receive calls on a Japanese phone number
• If you want to register a phone number as a contact
• If you want to receive SMS
• If you want to call someone who does not use LINE
• If you will be using regular calls for business trips or long stays

If you only need SMS authentication, you can keep your usual SIM for SMS reception and use a travel data-only eSIM.

The necessary communication methods for overseas travel depend on the need for regular calls, SMS, and data communication.

For short trips where a phone number is not needed, choose a plan from Japan eSIM Products and Pricing Plans that fits your travel days and data capacity.

If you need phone or SMS services, please check Phone Number with eSIM.