Having reliable Internet connectivity would greatly improve our ability to navigate our holiday in Japan. Many people discuss between eSIM and pocket Wi-Fi when planning Japan holiday. However, these are not the only choices and writing only about them would not paint a complete picture. This article aims to explain our choices when travelling to Japan, especially for first time visitors. Understanding each option and its benefits would help us in making informed decisions.

Why would we need to have Internet connection while in Japan? Can we just rely on free Wi-Fi?
We would need Internet connection in Japan to be able to perform at least 2 important activities: navigation (Google Maps or other app of your choice) and translation (Google Translate or other app of your choice). While most hotels and some restaurants do provide free Wi-Fi, it is not nearly enough for us to navigate throughout the holiday. There will be a lot of places where we need to check maps on our phone to navigate, and no place nearby offer free Wi-Fi. You will need reliable Internet connection that stays with you.

Chances are, you have a smartphone and can access Internet without problem in your home country. Whether you do prepaid or postpaid mobile, your plan is likely give you certain quota for Internet data usage, and maybe some quota for making traditional (voice) phone calls and sending text messages. For vast majority of cases, these data allowances are for use only in your home country. It means, when you go overseas doing international roaming with your smartphone, very different pricing structure will apply. For most people, roaming costs are expensive.

Technically speaking, you can simply use your current mobile operator to roam while in Japan. It is recommended to give them a call to make sure that they do not put a lock for international roaming on your plan. Ask them the international roaming costs. Note that many mobile operators have different pricing for visiting different countries, so make sure you are getting the right costs for roaming in Japan. Some plan requires you to pay expensive costs for every MB of data that you use overseas, as well as every second you use for phone calls and every text message you send. Some would even charge you to receive phone calls, which normally free in your home country. If you have eligible mobile plan, your network operator might charge you daily cost instead of itemised costs. The daily cost could be $5, $10 or $12. This might seem small, but it would quickly add up after we multiply it with the number of days of our holiday and the number of people in your family/group who needs mobile connection on their phones. For example, if a family of 4 (2 adults and 2 teenagers each owning a smartphone) want to go to Japan for 14 days, daily cost of $10 would translate into $10 x 14 x 4 = $560.

If money is no issue for you, you can stop reading this article at this point and continue with your life :)

If you wish to save some money, then continue reading. There are cheaper solutions to having Internet connection during our holiday in Japan.

Data-only SIM

First topic to explain is that Japan law is quite strict about allowing anyone to have Japanese mobile phone number. Simply buying a prepaid SIM card with local number like what we can do in many other countries is simply not an option in Japan. The vast majority of tourists can only get local SIM card only for Internet connection with data allowance, commonly referred to as data-only SIM. This means, data-only SIM card cannot be used to make traditional phone calls to land line numbers or other mobile phones. Thankfully, there are Internet-based apps allowing us to call each other using only Internet data, such as WhatsApp, FaceTime and some others. Using data-only SIM, a family enjoying holiday together in Japan would be able to call each other, even though data-only SIM card still do not have the ability to make phone calls to normal landlines such as business phones or any number that is not a smartphone with compatible app.

Getting a data-only SIM has some benefits:

  • Everyone in your family or travel group can get their own SIMs, and everyone can call each other during holiday.
  • There is no need for everyone to stay close together at all times during holiday for the Internet connection to work.
  • Can use Internet-based calling apps to make or receive voice or video calls.
  • Can use Internet-based messaging apps to send or receive messages.
  • There is no need to charge any additional hardware.
  • The cost is significantly cheaper compared to international roaming from home mobile operator.

Data-only SIM limitations:

  • Cannot make or receive traditional voice phone calls.
  • Cannot send or receive traditional text messages.
  • Need to buy the SIM for each person in the family or group.

Voice-and-Data SIM

Mobile connection with Japanese phone number is not intended for short term visitors under 90 days. People who live in Japan for more than 90 days (for example, student or people on work visa) can take up some plan that would give them Japanese phone number, which is required for many administrative things such as opening bank account and renting a house.

Even though it is not common, it is technically possible for tourist visiting Japan to have this voice-and-data SIM. There are at least 2 providers that I am aware of: Mobal and Sakura Mobile. Mobal even has voice-and-data SIM for 30, 60 and 90 days. The cost, however, is significantly higher than data-only SIM.

Benefits of voice-and-data SIM:

  • All benefits from data-only SIM.
  • Can make or receive traditional voice phone calls.
  • Can send or receive traditional text messages.
  • Can get Japanese mobile number.

Voice-and-data SIM limitations:

  • Higher cost.
  • The registration process is a bit tedious. We need to provide a lot more data to purchase voice-and-data SIM, including passport scan and our home address. This is to comply with strict Japan law about voice-and-data services. Buyer cannot fake the home address because the SIM that we purchase must be sent to that address.

eSIM

Both data-only SIM and voice-and-data SIM are available in 2 forms: physical SIM card and eSIM. Everyone knows the traditional physical SIM cards that we put into our mobile phones for decades. eSIM is basically a digital version of that. Many people seem to mistakenly associate eSIM being data-only. This is not true. Even a long-term mobile plan in Japan with Japanese mobile number can come in eSIM format.

To understand more about eSIM, we need to understand how physical SIM card works. Our mobile phone has the hardware capability to connect to any operator with compatible signal. This means, our mobile phone can essentially connect to any network, but it needs the information which network it should connect to depending on your mobile provider. If a phone connects to a wrong network, the network will not provide any service to the phone, making it useless.

A physical SIM card is basically a small data storage that stores our unique International Mobile Subscriber Identity (IMSI), our network plan details, and (optionally) our contacts. When we turn on our phone, it uses the IMSI and other keys on the SIM card to verify your identity with the network, granting us access to mobile services, which could be voice calls, text messages or Internet connection.

In simple terms, in order for a mobile phone to connect to the correct network and get access to its services, all it needs are IMSI and some keys data. The physical form of a card with chip is just a way to store these data. In the olden days before every phone uses Internet, it made sense that these data need to be stored somewhere so that when a mobile operator sells a service to us, it can tell our phone how to connect to the service.

Now that the vast majority of mobile phones have Internet connection, the need of physical chip in a tiny card form factor is no longer the only option. Many mobile companies now allow their customers to connect to their services using the same data (IMSI, the connection keys, network plan details) delivered to the phone digitally, this is called eSIM or electronic SIM.

There are two methods to deliver eSIM to a mobile phone:

  • Using QR code
  • Directly installed from an app

When we purchase 5 or 10 GB data-only eSIM from a provider, we do not actually “buy” the eSIM, we buy the service. eSIM is just a method of delivery. Some providers would actually send us a new SIM for every block of data that we purchase while others allow us to use the same eSIM but we can top up the data (updating the service).

Not all mobile phones support eSIM. As a general guide, older smartphones are usually not eSIM compatible. To use an eSIM, your phone needs to be network-unlocked and support eSIM. Check if your phone’s locking status and eSIM support before purchasing an eSIM service. Many modern smartphones can save multiple eSIMs (8 or even more), but we can only activate 2 at the same time (could be 2 eSIMs or combination of 1 eSIM and 1 physical SIM).

Even if your phone does not support eSIM, if it is not network-locked. You can still get data-only physical SIM or voice-and-data SIM for Japan.

Popular eSIM providers for Japan include Airalo, Ubigi, Mobal, Sakura Mobile, GigSky, FlexiRoam, TravelKon, Simify, and ByteSim. A lot of these providers are actually resellers. They do not own a mobile network in Japan. Instead, they partner with some network operators in Japan (KDDI, NTT Docome, Softbank, etc) and they resell some blocks of data to us. From time to time, they can change their partnership. An eSIM provider could partner with KDDI last year and then change to Softbank this year, resulting in different speed and connection quality. Even when partnering with the same network provider, the level of service that they bought (to sell to us) can change. If we use an eSIM brand and have good experience with it, it does not guarantee that it will always provide us the same quality when we use it again a few years in the future.

Airalo is one of the most popular eSIM providers for Japan. I have good personal experience with it. The connection was stable and their app is quite user friendly. We can purchase a service first and then activate the service later. This can be useful because we can buy the service a bit earlier when it is on sale. There is also member-get-member scheme that would get us a small discount if we purchase a service with promo code from someone else. The downside of Airalo is that its connection speed is limited to 4G.

Ubigi is another popular eSIM provider for Japan. It offers 5G speed, making it my personal favourite. Ubigi service would automatically starts on the day of purchase, so we cannot buy it earlier. My suggestion is to buy in in the morning before our flight to Japan. Ubigi app is also looking good and easy to use. There are discount codes available for Ubigi. Just join one of those Japan travel groups in social media and you can easily obtain one.

Both Ubigi and Airalo are installing eSIM from their apps. Their eSIMs can be used multiple times and can stay in your phone as inactive when not being used. We can top-up more data into the eSIM if required.

Mobal is the only provider I know that offer voice-and-data SIM for short term visitors. They offer physical SIM and eSIM for 30, 60 and 90 days. If we purchase physical SIM, it will be shipped to our address. If we purchase eSIM, they will mail print out code for us to install the eSIM to our home address. This is due to legal compliance to Japan law. There is also an option of free pick-up in Japan location, but I have not personally tried this option.
We get real Japanese mobile number from Mobal and we can use it to make or receive calls to/from shops and businesses. The Internet connection is stable. The only downside of Mobal SIM is that we need to download APN setting. This prevents us from activating 2 SIMs at the same time for supporting phones (could be 2 eSIMs or 1 eSIM and 1 physical SIM) because the APN from Mobal SIM (eSIM or physical) seems to prevent the other active network to function properly.

TravelKon is an Australian company offering eSIM for various countries including Japan. It sells both data-only eSIM and physical SIM. Since I have a smartwatch that has 4G connectivity using a SIM card, getting data-only physical SIM from TravelKon makes a good solution. For eSIM, TravelKon would email us QR code after purchase. We scan the QR code when we are ready to start our holiday.

When you buy some attraction tickets from Klook, you might also get free eSIM from your transaction. Their free eSIM usually do not have large amount of Internet data (1 GB or 3GB), but if your trip duration is short, this could be a cheap solution. After all, free stuff means happy saving.

Different eSIM providers have different mechanism of activation. Some providers will activate your eSIM when you are connected to a supported network (you arrive in destination country). Some require us to press a button “activate” in their app or website. Some others would activate the eSIM services instantly after purchase (such as Ubigi), so always make sure to read carefully.

eSIM installation requires stable Internet connection. I would recommend to install eSIM on the day of departure, but while still in home country with stable Internet connection (such as our home Wi-Fi). Sometimes eSIM installation would show error message of cannot connect to network, this is normal when we install eSIM in our home country.

eSIM is likely slightly cheaper than equivalent physical SIM because they do not need the cost to produce the physical SIM. However, the cost difference is likely not much. Many people like eSIM and recommend it because of its simplicity, it can be purchased before the trip and there is no need to receive any physical delivery, everything can be done on the phone and instantly configured.

Sometimes we arrive in Japan with pre-purchased SIM, only to find out that somehow it does not work. You might be able to resolve it with troubleshooting steps:

  • Turn off (deactivate) the eSIM from your phone setting, wait for 3-5 minutes then turn it on again. Note that deactivating eSIM is different from deleting eSIM, do not delete the eSIM.
  • Turn on Aeroplane mode, wait for 3-5 minutes, then turn it off again.
  • Restart the phone.
  • Make sure data roaming for that particular eSIM is on. Some eSIM providers require this setting to be on.
  • Make sure your APN setting is configured as per instruction from your eSIM provider (if any).
  • Check if there is any VPN configured in your phone. Many eSIM settings do not play well with VPN.

If my phone supports eSIM, can I choose physical travel SIM anyway? Generally eSIM option will be slightly cheaper than equivalent physical SIM option. However, physical SIM has a benefit that it can be moved to another phone if needed while eSIM cannot be moved to another device once installed. If this scenario applies to you, getting physical SIM is a valid option.

Pocket Wi-Fi

Pocket Wi-Fi is a small device that has Internet through cellular connection (4G or 5G) and is able to share that connection to multiple devices nearby. This means, one pocket Wi-Fi can give Internet connectivity to a few devices. Most pocket Wi-Fi can handle 5 devices, some of the more expensive models can handle 10 devices. Many pocket Wi-Fi rentals in Japan has unlimited data and the cost is calculated per day.

From the perspective of your phone, it will detect the pocket Wi-Fi as an available Wi-Fi connection just like in your home or office, but this Wi-Fi connection will follow wherever the pocket Wi-Fi goes. Not only phones, it would also work with tablet and even laptop. The pocket Wi-Fi itself runs on battery. One full charge usually lasts between 4 to 8 hours. Some rental services also include powerbank as part of the package so that it stays powered longer.

Benefits of pocket Wi-Fi:

  • Works even with network-locked phones.
  • Multiple devices can get Internet connection. This means one pocket Wi-Fi can be shared for multiple people, such as family members travelling as a group.
  • Can use Internet-based calling apps to make or receive voice or video calls.
  • Can use Internet-based messaging apps to send or receive messages.
  • The cost is significantly cheaper compared to international roaming from home mobile operator.

Pocket Wi-Fi limitations:

  • Everyone needs to stay close together at all times during holiday for the Internet connection to work. If anyone in the group gets separated, or somehow moved to a location more than 20 metres from the pocket Wi-Fi, that person will lose Internet connection and rest of the group will not be able to contact him/her.
  • The pocket Wi-Fi is an additional item to carry.
  • The pocket Wi-Fi needs to be charged. If it runs out of battery, no one gets Internet connection.
  • Cannot make or receive traditional voice phone calls.
  • Cannot send or receive traditional text messages.

Some people rent the pocket Wi-Fi before their trip, collect the device at the airport, and return it at the end of their holiday. Some rental services also offer delivery to Japan hotels. There are a few common ways to return the pocket Wi-Fi device: return at the airport, return to participating hotel lobby, or mail it in the nearest post office or post box using the pre-paid return envelope provided from the start.

What is the difference between Wi-Fi and eSIM? Wi-Fi is a technology that allows wireless connection within short distance (20 metres or less), it cannot be used to obtain Internet connection far from where the Wi-Fi source is. The Pocket Wi-Fi device itself has Internet through cellular connection (4G or 5G), and then share it to people nearby using Wi-Fi technology.
eSIM is a technology to allow a smartphone to connect to a mobile network through cellular connection (4G or 5G). No Wi-Fi is involved in eSIM because the mobile phones directly gets its services and Internet connection from the mobile network.

How to Choose?

How do we choose which Internet solution to use for a holiday in Japan? I tried making simple flowchart to help with decision making.

  • If money is no issue and you don’t mind paying the premium cost of international roaming, then there is nothing to decide, you can just continue using your home number.
  • If you wish to save some money, then check if your phone is network unlocked.
  • If your phone is network-locked, renting pocket Wi-Fi is your option.
  • If your phone is network-unlocked, then you have the option of getting travel SIM. Next is deciding if you need Japan mobile number to be able to make (traditional) voice calls or not.
  • If you do not need Japan mobile number to make traditional voice calls, then you can choose between pocket Wi-Fi, data-only physical SIM or data-only eSIM. Review the benefits and limitations from the above sections. If your phone supports eSIM, generally eSIM option will be slightly cheaper.
  • If you need Japan mobile number to make traditional voice calls, then you can choose between voice-and-data physical SIM or voice-and-data eSIM.

Others

This post is one of five parts of Planning Japan Holiday series:

Lastly, the information in this post are based on my knowledge at the time of writing. Things can change. This article is written to help first time visitors with a starting point to plan their trips. Always check with official sources for latest information when doing the actual planning.