When planning a trip to Japan, many people may wonder, "Do I need a SIM card to use my smartphone in Japan?" and "Which is better, a SIM card or eSIM?"
To use mobile data in Japan, there are several options available, including SIM cards, eSIMs, rental Wi-Fi, and international roaming.
Among these, SIM cards and eSIMs are convenient methods that allow you to communicate using just your smartphone without carrying a Wi-Fi router. However, there are differences in terms of delivery, setup, and compatible devices.
This article explains whether a SIM card is necessary for traveling in Japan and clearly introduces the advantages and disadvantages of SIM cards and eSIMs, as well as how to choose between them.
If you want to check the features, pricing, and setup methods for Japan eSIM at a glance, please also refer to the Complete Guide to Japan eSIM.
Is a SIM card necessary for traveling in Japan?
You do not necessarily need a physical SIM card to use your smartphone while traveling in Japan.
If your smartphone supports eSIM, you can add a Japan eSIM to your device without swapping SIM cards and use mobile data.
On the other hand, if the smartphone you are using does not support eSIM, you will need to consider options such as a SIM card, rental Wi-Fi, or international roaming.
In other words, whether you need a SIM card mainly depends on the following conditions.
- Is your smartphone eSIM compatible?
- Is the SIM lock removed?
- Do you need a phone number or SMS?
- Are you comfortable with swapping physical SIM cards?
- Do you want to prepare your communication method before traveling?
| Usage Conditions | Recommended Communication Method |
|---|---|
| Using an eSIM-compatible device | eSIM |
| Using a non-eSIM-compatible device | SIM card or rental Wi-Fi |
| Do not want to swap SIM cards | eSIM |
| Want to use a physical SIM | SIM card |
| Want to share communication among multiple people | Rental Wi-Fi or tethering-compatible eSIM |
What is a SIM card?
A SIM card is a small IC card that is inserted into a smartphone for use.
The SIM card contains information about your contract and the communication services you can use, allowing you to utilize mobile data by inserting it into a compatible smartphone.
SIM cards for traveling in Japan can be purchased online before your trip, or they may be available for purchase at Japanese airports, electronics retailers, and stores.
Advantages of SIM cards
- Can be used even with non-eSIM compatible devices
- Easy to understand for those familiar with physical SIMs
- May allow the use of phone numbers and SMS with compatible products
- May require relatively few changes to smartphone settings
Disadvantages of SIM cards
- Requires receiving the SIM card
- Need to swap the smartphone's SIM card
- Must store your regular SIM card
- Risk of losing a small SIM card
- May require a SIM pin to open the SIM tray
- Purchasing after arriving in Japan may take time before you can start using it
What is eSIM?
eSIM is a communication method that utilizes the SIM functionality built into the smartphone itself.
There is no need to insert a physical SIM card into the device; instead, you can add a communication plan to your smartphone using a QR code or setup information that you receive after purchase.
If you add an eSIM before your trip, you can turn on the relevant line upon arrival in Japan and switch to mobile data communication to start using it.
Advantages of eSIM
- No need to swap SIM cards
- No need to pick it up at the airport or store
- No need to remove your regular SIM card
- No worry about losing a SIM card
- Can be purchased and set up online before the trip
- Easy to start communication immediately upon arrival in Japan
- No need to carry or return a Wi-Fi router
Disadvantages of eSIM
- Requires an eSIM-compatible smartphone
- Need to check the SIM lock status of the device
- First-time users may find the setup confusing
- If deleted by mistake, it may not be possible to reconfigure
- May not be transferable to another device or during a device change
You can check the plans available for use in Japan at the Japan eSIM product page.
Comparing the differences between SIM cards and eSIMs
Both SIM cards and eSIMs are methods for using mobile data on smartphones, but there are differences in terms of delivery and setup methods.
| Comparison Item | SIM Card | eSIM |
|---|---|---|
| Form | Physical card | Built-in type |
| Delivery | Required | Generally not required |
| Setup Method | Insert SIM card | Add with QR code or setup information |
| SIM Swap | Required | Not required |
| Regular SIM | May need to be removed and stored | Can remain in the device |
| Risk of Loss | Yes | No risk of losing a physical card |
| Delivery Time After Purchase | May require shipping or store pickup | Receive setup information online |
| Compatible Devices | Requires a compatible SIM slot | Requires an eSIM-compatible device |
| Reconfiguration | May be transferable to another device | May not be reinstallable |
| Recommended For | Those with non-eSIM compatible devices | Those who want an easy setup |
Which is recommended for traveling in Japan, a SIM card or eSIM?
For solo travelers, short trips, business trips, or temporary returns, eSIM is recommended as it does not require pickup or SIM swapping.
On the other hand, for those using smartphones that do not support eSIM or who find physical SIM cards easier to use, a SIM card is more suitable.
Recommended for eSIM
- Those using eSIM-compatible smartphones
- Those who do not want to swap SIM cards
- Those who want to prepare their communication before traveling
- Those who do not want to search for a SIM card at the airport
- Those who want to use the internet immediately upon arrival in Japan
- Those who want to keep their regular SIM card in the device
- Those traveling for a short trip, business, or temporary return
Recommended for SIM cards
- Those whose smartphones are not eSIM compatible
- Those familiar with setting up physical SIM cards
- Those who are anxious about the additional setup for eSIM
- Those who want to use a SIM card with a compatible phone number
- Those who may need to swap SIM cards between multiple devices
For solo travelers, eSIM is recommended
For solo travelers, eSIM is convenient as there is no need to share communication, allowing you to use just your smartphone.
There is no need to pick up or swap SIM cards, and you do not have to worry about storing a small SIM card during your trip.
It is also suitable for those who want to use maps, transit guides, translation apps, and social media immediately upon arrival in Japan.
How to choose for family or group travel?
For family or group travel, if each smartphone is eSIM compatible, everyone can use eSIM individually.
If each person has their own communication method, they can use maps and messaging apps even if they are separated.
If you want to stay together and consolidate communication costs, using rental Wi-Fi is also an option.
If you are unsure whether to choose Wi-Fi or eSIM for your trip to Japan, please refer to the comparison article on Wi-Fi and eSIM.
What if you need a phone number or SMS?
Travel SIM cards and eSIMs come with either data-only plans or plans that support phone numbers and SMS.
With a data-only plan, you cannot make calls or send SMS using a regular phone number.
However, if you have data access, you can use messaging apps like LINE, WhatsApp, and Messenger for messages and internet calls.
If you need the following functions in Japan, check the availability of phone numbers and SMS.
- Calling hotels or restaurants
- Registering for ride-hailing services
- SMS verification
- Registering for local services
- Contacting using a regular phone line
If you need a phone number, please check the eSIM plan with a phone number.
Things to check before purchasing a SIM card or eSIM
Check device compatibility
If you are using eSIM, your smartphone must be eSIM compatible.
Before purchasing, please check the list of eSIM-compatible devices.
If you are using a SIM card, also check the size of the SIM card and the compatible frequencies of your smartphone.
Check SIM lock status
If your smartphone has a SIM lock, you may not be able to use a travel SIM card or eSIM.
Check the SIM lock status from your current carrier or the device's settings menu.
Check the usage period
If you choose a plan shorter than your travel days, you may lose access to communication before returning home.
Choose a plan that allows for flexibility from your arrival date in Japan to your departure date.
Check data capacity
The required data capacity varies depending on how you use your smartphone during your trip.
| Usage Style | Daily Estimate |
|---|---|
| Maps and messaging focused | About 500MB to 1GB |
| SNS and photo posting | About 1 to 2GB |
| Video and video calls | About 3GB or more |
| Frequent tethering use | Large capacity or unlimited |
For more details, please refer to the estimated data usage.
Check the start conditions for use
The timing for the start of the eSIM usage period varies by product, such as at the time of installation or when connecting to a Japanese network.
If you are setting it up before your trip, please check the instructions after purchase or on the product page.
How to set up Japan eSIM
Japan eSIM can generally be used by following these steps.
- Check the number of days you will stay in Japan and the data capacity you need
- Purchase a Japan eSIM plan
- Receive the QR code or setup information
- Add the eSIM to your smartphone in a stable Wi-Fi environment
- Turn on the Japan eSIM line after arriving in Japan
- Select the Japan eSIM for mobile data communication
- Turn on data roaming if necessary
For detailed setup methods for iPhone and Android, please refer to the eSIM setup guide.
Troubleshooting if eSIM does not connect
If you cannot connect with eSIM after arriving in Japan, please check the following items.
- Is the eSIM line turned on?
- Is the Japan eSIM selected for mobile data communication?
- Is data roaming turned on?
- Is the APN setting correct?
- Have you tried toggling airplane mode on and off?
- Have you restarted your smartphone?
If you cannot connect, do not delete the eSIM immediately. Once deleted, it may not be possible to reconfigure with the same QR code.
For more details, please check the troubleshooting for eSIM.
Frequently Asked Questions
Do I have to purchase a SIM card for my trip to Japan?
You do not necessarily have to purchase a physical SIM card.
If your smartphone is eSIM compatible, you can use a Japan eSIM. You can also consider options like international roaming or rental Wi-Fi.
Which is cheaper, a SIM card or eSIM?
The price varies depending on the number of days of use, data capacity, communication speed, and whether a phone number is included.
Be sure to compare not only the product price but also the shipping costs for the SIM card, pickup methods, and any additional capacity for the eSIM.
Can I still use my regular SIM card with eSIM?
On dual SIM compatible devices, it may be possible to keep your regular SIM card in the device while adding a travel eSIM.
However, be careful with the data roaming settings for your primary line to avoid unintended international roaming charges.
Can I purchase a SIM card after arriving in Japan?
You may be able to purchase one at airports, electronics retailers, and stores.
However, it may take time depending on stock availability, business hours, and the procedures for starting use.
Can I purchase eSIM after arriving in Japan?
If you have access to the internet, you can purchase it even after arriving in Japan.
Since airport Wi-Fi can be unstable, it is advisable to purchase and set it up before your trip for peace of mind.
If I delete eSIM, can I reuse it?
Depending on the product, once deleted, it may not be possible to reinstall it with the same QR code.
If you encounter communication issues, do not delete it immediately; check the settings or contact support.
Can I use a SIM card and eSIM at the same time?
On dual SIM compatible devices, it may be possible to register both a physical SIM card and an eSIM in the device at the same time.
Some devices allow you to set the regular SIM for calls and the Japan eSIM for mobile data.
Conclusion
You do not necessarily need a physical SIM card to use your smartphone while traveling in Japan.
If your smartphone is eSIM compatible, you can use Japan eSIM, which does not require receiving or swapping SIM cards.
For solo travelers, short trips, business trips, or temporary returns, eSIM is recommended as it can be purchased and set up before the trip, allowing for easy communication immediately upon arrival in Japan.
On the other hand, those using non-eSIM compatible devices or who find physical SIMs easier to use should opt for a SIM card.
Check your device compatibility, SIM lock status, duration of use, data capacity, and the necessity of a phone number to choose the communication method that best fits your travel style.
