This article is based on official guidance from companies and organizations, and this site’s phone and internet articles, as of October 2026.
eSIM, SIM card, pocket Wi-Fi. The more you research, the more each one starts to look like a good choice.
This article is for anyone stuck at that point. We’ll keep the explanation short and give you the answer first.
The answer first — this is our short answer
If one person will use one phone, start with an eSIM. If your phone supports eSIM and has no SIM lock, this is what we would choose.
Only move to one of the other two if that does not fit.
- Your phone does not support eSIM → SIM card (provided the phone has no SIM lock)
- You want to share with family or companions across several devices / you cannot remove the SIM lock → Pocket Wi-Fi
There is one more option: roaming, using your usual phone as it is. If your home carrier has a plan that works in Japan and you can confirm its price and conditions before departure, that can also be a choice.
This article does not compare which is fastest, cheapest, or how many GB you need per day. Those things vary with the way you travel, the company, and the plan, so there is no reliable single yardstick. Base your decision on your phone and how many people need to connect how many devices.
First, check your phone
The answer depends on two things about your phone.
- Is it free of a SIM lock? On an iPhone, go to Settings → General → About. If Carrier Lock says “No SIM restrictions,” you are fine. If the phone is locked, neither an eSIM nor a SIM card will work
- Does it support eSIM? For iPhones, that means iPhone XS, XS Max, XR, or later. However, some iPhones bought in mainland China do not support eSIM. Some models sold in Hong Kong and Macao take two physical SIM cards. If you bought your iPhone in one of these regions, check the specifications of your exact model first. For Android phones, it depends on the model (Google Pixel 3a or later; some Samsung phones may not support eSIM depending on the country of purchase, even when the model name is the same)
There is also the reverse exception: eSIM-only phones with no place to insert a SIM card. Recent iPhones bought in places such as the United States are like this. See “SIM Card” for which models these are.
For details on how to check, see “eSIM.”
Who should choose an eSIM
- You are traveling alone, or everyone will connect using their own phone
- Your phone supports eSIM and has no SIM lock
An eSIM is a travel plan you buy online and install inside your phone. You can install it over your home Wi-Fi before departure, so you do not have to look for a sales counter after landing. Because there is no card to swap, you do not risk removing and losing your home SIM. There is nothing extra to carry and nothing to return on your last day.
Just remember these points.
- When the validity period starts depends on the company and plan. With Airalo, for example, in most cases it starts when the eSIM first connects to a supported network in Japan. For other companies and plans, check the explanation before buying
- Do not delete an installed eSIM. Once a travel eSIM has been deleted, it usually cannot be reinstalled
- If you want to share the connection with a tablet or computer, check before buying whether tethering is available. It depends on the phone and network
For installation, switching after arrival, and what to do if it will not connect, see “eSIM.”
Who should choose a SIM card
- Your phone does not support eSIM (but has no SIM lock)
- Swapping a card feels easier than setting up an eSIM
You swap your home SIM for a travel SIM card. While your home SIM card is removed, that line does not operate in Japan (if your home line is an eSIM, turn off data roaming for that line).
You can buy one at airports (vending machines at Narita and Kansai, counters in Haneda Terminal 3, and elsewhere) or at electronics stores. If your flight arrives late at night, buying one online before coming to Japan is another option.
Keep your passport at hand on the day you buy or insert it. Some companies require a passport check. SoftBank’s travel SIM, for example, requires a photo of the original passport, and people under 18 cannot sign up.
Keep the SIM you removed somewhere safe. You will need it again after returning home.
For places to buy and how to insert it, see “SIM Card.”
Who should choose pocket Wi-Fi
- You want one device to connect several phones or tablets for family or companions
- Your phone has a SIM lock that you cannot remove before departure
- You want to connect a device that supports neither eSIM nor a SIM card
Pocket Wi-Fi means renting a Wi-Fi device and carrying it with you. Your phone simply connects to that Wi-Fi. Because you do not replace the SIM in your phone, its SIM lock does not matter. The number of devices you can connect varies by model; Japan Wireless, for example, allows up to eight.
In return, there are a few extra tasks.
- Decide how to receive and return it when booking (airport counter, unattended box, or delivery to your accommodation / return by post or in a box; the choices vary by company)
- Charge it every night
- Assume that anyone away from the device will lose the connection. On days when your family splits up, decide who will carry it
- It does not come with a phone number. You cannot call 110 or 119 through pocket Wi-Fi
For how to receive and return one, see “Pocket Wi-Fi.”
If you need a Japanese phone number
Many travel eSIMs, SIM cards, and pocket Wi-Fi products provide data only and do not include a Japanese phone number.
Even without one, most trips work out fine. The main times you need a number are for verification codes sent when registering for an app and for calls in an emergency.
- Keeping your home number can help. On an iPhone, you can keep your home number while using a travel eSIM for data only. In some cases, you can also continue using FaceTime and iMessage with your home number. How much of your home number works in Japan, and what it costs, depend on your home carrier’s settings and charges. Check with the provider before departure
- If you truly need a Japanese number, some SIM cards and eSIMs come with a Japanese number beginning with 070, 080, or 090. For example, Mobal’s SIM with a phone number requires the original passport, and people under 18 cannot apply
- An internet phone number beginning with 050 is different. Brastel’s My 050, for example, cannot call 110 or 119 and cannot receive SMS
With a data-only SIM, you may be unable to call 110 (police) or 119 (fire and ambulance). If that happens, ask staff at your accommodation or a shop, or someone nearby, for help. For handling verification codes and emergencies, see “When You Need a Japanese Phone Number.”
Before you go, just these things
- You checked that your phone has no SIM lock and supports eSIM
- If using an eSIM, you installed it over your home Wi-Fi. Do not delete the installed eSIM
- If keeping your home number, you have a plan to turn off data roaming only for your home line (set the travel line as instructed by its provider)
- If using a SIM card, keep your passport at hand
- If using pocket Wi-Fi, check the pickup place, return method, and return deadline in your booking confirmation
- If using roaming, confirm your home carrier’s plan and price
If both the travel line and home line remain on, your home line may incur roaming charges. Turn off data roaming only for your home line.
More details
- An overview of every option → “How to Get Your Phone Online in Japan”
- How to install an eSIM and switch after arrival → “eSIM”
- Where to buy and how to insert one → “SIM Card”
- How to receive and return one → “Pocket Wi-Fi”
- If you forgot to install it, use the airport’s free Wi-Fi → “Free Wi-Fi”
- Situations where you need a number → “When You Need a Japanese Phone Number”
- You arrived but cannot connect → “When You Can’t Get Online”
If you are unsure, open your phone and check only two things: no SIM lock and eSIM support. If both are in place, install the eSIM the night before (or just before arrival if its validity starts at installation), then switch to it at the airport after landing.
