A Japanese voice number is the key that unlocks everything else — banks, apartments, and job applications all ask for one — yet the classic contract requires a Japanese bank account or credit card you don't have yet. The way out is a budget carrier that accepts foreign credit cards for a real voice plan in week one, then switching freely later, since cancellation lock-ins and SIM locks are largely gone.
Key facts
- Documents for a voice contract
- Residence card + payment method
- Budget lines (MVNO/online plans)
- ~¥1,000–3,000/month for 3–20GB
- Big-three carriers
- ~¥5,000–8,000/month, shop support
- Cancellation penalties
- Largely abolished since 2021–22
- SIM lock on new handsets
- Banned since October 2021
Day one vs week one
Day one, any airport data SIM or eSIM keeps you online — maps, translation, messages. But the item everything else waits on is a voice number: your bank account, apartment screening, and employer paperwork all want a 070/080/090 number that answers. So the real task in week one, residence card in hand, is a proper voice contract — and the good news is that this no longer requires a trip to a carrier shop or a Japanese credit history.
Breaking the chicken-and-egg loop
The old trap: the phone contract wants a Japanese bank account or credit card, and the bank wants a Japanese phone number. The break point is a budget carrier or online plan that takes a foreign-issued credit card — sign up by app, receive the eSIM the same day, and walk into the bank with a working number. From there the order corrects itself: bank account, then (optionally) move the phone billing onto it.
What a sane bill looks like
Budget lines and online-only plans from the big carriers ride the same towers as the flagship brands for ¥1,000–3,000 a month; the ¥5,000–8,000 flagship plans mainly buy shop-counter support. Two regulatory changes tilted the game toward switchers: cancellation penalties were effectively abolished, and new handsets have been sold SIM-lock-free since October 2021 — so the phone in your pocket from home almost certainly works, and hopping to a cheaper carrier each year via MNP is normal behavior, not rudeness.
Common mistakes & warnings
- A data-only SIM from the airport gets you online but has no phone number — banks, city hall callbacks, and delivery drivers need a real 070/080/090 voice number, so treat the data SIM as a bridge, not a solution.
- Never sign a contract you can't read at a carrier shop — old-style plans bundled with options and handset "deals" are where overpaying hides. The advertised price and the first bill can differ by thousands of yen in options you never asked for.
- Keep the number alive if you leave Japan temporarily — losing it can lock you out of banking apps and LINE, since Japanese services verify by SMS to that number.
Frequently asked questions
Can I get a phone contract before I have a Japanese bank account?
Yes — several budget carriers and online plans accept foreign-issued credit cards, which breaks the loop. Get the voice number first, open the bank account with it, then switch billing to the Japanese account or card if you like.
Should I choose a big carrier or a budget line?
Budget lines and the big carriers' own online plans use the same physical networks at a third of the price; the premium buys in-shop, sometimes multilingual, support. If you can follow an app-based signup, the budget option is rarely the wrong call.
Can I keep my number when switching carriers?
Yes — MNP portability lets you carry the number over, and reservation numbers can now be issued online in minutes. Since penalties were scrapped, switching yearly to whoever is cheapest is a normal strategy.
Official sources
This page provides general information only and is not legal advice. Immigration rules change; always confirm details with the official sources listed above before making decisions.