Your residence card may still be on its way, your address may still be temporary, and yet nearly every step of settling in seems to need a working phone. On top of that, you have to choose between a prepaid SIM and a monthly plan before you know how your first year will go. This guide explains what each option suits and how to pick one without locking yourself into the wrong setup.
What prepaid and monthly actually mean in Japan
A prepaid SIM or eSIM is paid once, up front, for a fixed period. In the shibaSIM catalogue, prepaid plans cover 3 to 12 months. You pay one amount, you use the data, and there is no monthly fee. When the period ends, you choose a new plan or move on to something else.
A monthly plan works like an ongoing subscription. You pay each month and the service continues until you cancel. Monthly plans come as data SIMs or voice SIMs, as a physical card or as an eSIM, and they run on major Japanese networks such as Docomo, SoftBank and Rakuten. There is also an AU option meant for home Wi-Fi rather than for your phone.
The real difference is not only how you pay. It is how much paperwork the plan needs, whether it includes SMS or a callable number, and how well it fits the length of your stay. Those three points should drive your decision more than the label prepaid or monthly.
Your first days: before the residence card arrives
Newcomers often find that their residence card and registered address are not ready in the first days. Plans with a callable Japanese number need identity verification, and that usually means a valid residence card and your current address in Japan. Until both exist, you cannot complete that step.
A simple way through this gap is a travel eSIM. It needs no documents, it is valid for 5 to 30 days, and it runs alongside your home SIM, so you keep your own number for messages from family or your home bank. You pay online by card, and the QR code normally arrives within 30 minutes during support hours (8:00 to 22:00 JST). You can install it before your flight and have data when you land. You can see the travel eSIM options for Japan if you need cover for this stage.
Once your card and address are sorted, you move to a longer plan. This approach also gives you a few days to work out what you need. You will know whether your school, office or landlord wants a callable number, and you can choose your next plan with that information.
Tip: Check that your phone supports eSIM before you travel. iPhone XR/XS and later and most higher-end Android phones from 2019 are compatible.
When a prepaid SIM or eSIM makes sense
Prepaid works well when your stay has a clear length and your main need is data. Think of a semester abroad, a language course, or a working holiday where you expect to move around. You pay once, you know the total cost from the start, and you do not have to manage a monthly bill.
It also suits people who prefer to keep things simple. With no monthly fee, a forgotten payment cannot interrupt your service in the middle of the term. Prepaid is a predictable choice if you want to set up your phone once and focus on everything else.
The limit is flexibility around paperwork. If you will soon need a Japanese number for a bank account, a lease or a job application, check that the plan you choose actually includes one. Do not assume it does. The plans page shows what each option includes.
When a monthly plan is the better fit
A monthly plan usually fits better when you are staying long term, when your plans are open-ended, or when you need a real Japanese phone number for daily life. It continues as long as you need it, so you do not have to renew every few months.
Monthly plans also make sense when your usage might change. A student who later starts a part-time job, or a worker whose company asks for a reachable number, can choose a plan with voice from the start rather than switching later. Having the network options of Docomo, SoftBank and Rakuten also lets you pick based on where you live and work.
One thing to check is the contract terms. Any minimum term or cancellation fee is confirmed clearly before you finish signing up, so you know what happens if you leave Japan earlier than planned. Read that confirmation carefully, especially if your visa or contract dates are not fixed yet.
Do you need a real Japanese phone number?
This question often settles the choice. A number that can make and receive calls, starting with 090, 080 or 070, is usually needed to open a Japanese bank account, apply for jobs, sign a rental contract and register at many offices. Without one, those steps can stall.
Data-only plans work well for internet apps such as messaging, maps and video calls. They do not give you a callable number. Some plans include SMS, but SMS is only available when a plan explicitly includes it. Delivery of verification codes also depends on the app and the sender, so it is not guaranteed for every service.
If you already have a Japanese number and want to keep it, you need an MNP transfer code from your current carrier. Do not cancel your old contract first. If you do, the number is lost and cannot be brought over.
Student, Work or phone number plan: matching your situation
For residents, shibaSIM groups its main plans by situation rather than by technical details. The Student plan offers 5GB, data only, with no SMS and no phone number. It suits someone who mostly uses campus Wi-Fi and needs mobile data for maps, messages and study apps.
The Work plan offers 20GB and includes SMS, but not a callable number. It fits people who use their phone heavily for work apps and need to receive text codes from services that send them, but who do not need to make or receive calls on a Japanese number.
The Japanese phone number plan offers 20GB, SMS and a real mobile number starting with 090, 080 or 070 that can make and receive calls. If your first year includes opening a bank account, renting your own place or job hunting, this is usually the plan to look at. You can compare SIM and eSIM plans for living in Japan to see the current details and prices.
What to prepare before signing up
For plans with a callable number, prepare your valid residence card, your current address in Japan and a payment method in your own name. Staff explain every step before you send anything, so you will not be asked to share documents without knowing why.
Some providers require reading the IC chip of your residence card with NFC. If that applies, staff tell you in advance and guide you step by step. If your phone cannot read the chip, there is a fallback, so an older phone does not have to block your sign-up.
You do not need a Japanese credit card. Staff confirm a payment method that works for you in chat before you pay anything. If you are unsure about any step, support is available in English from 8:00 to 22:00 JST by WhatsApp or by email at [email protected]. Never send card details through chat or email. Only type them into the secure payment form.
Frequently asked questions
Can I get a SIM in Japan without a residence card?
Yes, for data. A travel eSIM needs no documents and works for 5 to 30 days, which covers most people while they wait for their card. Plans with a callable Japanese number need identity verification, so those come later, once your card and address are ready.
Is prepaid cheaper than monthly in Japan?
It depends on how long you stay and what you need. Prepaid means one payment and no monthly fee, while monthly continues until you cancel. Prices change, so compare the current prices shown on the plans page for the length of stay you expect.
Will a data-only SIM work for bank verification codes?
A data-only plan has no SMS and no phone number, so it cannot receive text codes. Even on plans that include SMS, delivery of codes depends on the app and the sender. Opening a Japanese bank account usually needs a number that can make and receive calls.
Can I switch from a travel eSIM to a monthly plan later?
Yes. This is a common path for newcomers. Use the travel eSIM for the first days, then move to a resident plan once your residence card and address are ready.
The takeaway
There is no single right answer for everyone. Start with a travel eSIM if your documents are not ready. Choose prepaid if your stay has a fixed length and data is your main need. Choose a monthly plan with a real number if your first year involves a bank account, a lease or a job. When you are ready to compare options for your situation, you can explore SIM and eSIM plans for residents, and the support team can help you check which one fits before you pay anything.
