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MNP in Japan lets you switch carrier and keep your number for free online. One-stop switching, reservation numbers, fees and keeping your number when you leave.
As of October 2026, MNP (mobile number portability) lets you switch carrier in Japan and keep your 070, 080 or 090 number. It is free online. Since May 24, 2023, the one-stop method lets you apply only at your new carrier's website. Otherwise you get an MNP reservation number, valid 15 days. Some carriers charge up to ¥1,100 if you leave within 12 months. If you leave Japan, docomo, au and SoftBank store your number for ¥409 to ¥440 a month, for up to 5 or 6 years.
MNP (mobile number portability, 番号ポータビリティ) lets you switch carrier in Japan and keep your 070, 080 or 090 number. Done online it is free. Since May 24, 2023, the one-stop method (MNPワンストップ) lets you apply only at your new carrier’s website, with no reservation number. Otherwise you get an MNP reservation number, valid 15 days. Some carriers charge up to ¥1,100 if you leave within 12 months. Rules are from the Ministry of Internal Affairs and Communications (総務省) and carrier pages, as of October 2026.
Switching with MNP is not a transfer of your contract. Your old contract is canceled and you sign a new one with the new carrier, keeping only the number. According to 総務省, that means:
You need a voice line. MNP may not be available for data-only services, and you can use MNP again later to go back to your old carrier or move on.
With one-stop MNP you do everything from the new carrier’s website. Both carriers must support it.
To check, ahamo lists the carriers you can move from with one-stop, as of March 2026. They include au, SoftBank, UQ mobile, Y!mobile, povo, LINEMO, Rakuten Mobile, mineo, IIJmio, NUROモバイル, BIGLOBEモバイル, イオンモバイル, OCN モバイル ONE, J:COM MOBILE and HISモバイル. 総務省 also bans retention tactics against people using one-stop.
You need your My Page login for the old carrier, so check you can log in before you start.
If your current or new carrier doesn’t support one-stop, use the two-stop method (ツーストップ方式):
ahamo says a reservation number is valid for 15 days including the day it’s issued, and it wants at least 10 days left when you apply. Sakura Mobile wants at least 8 days left. So apply soon after you get the number.
| Fee | Amount | Source |
|---|---|---|
| MNP fee (one-stop or online) | Free | 総務省 |
| Reservation number issued in person or by phone | Up to ¥1,000 + tax | 総務省 |
| Transfer-in fee at new carrier | None (a contract fee may apply) | 総務省 |
| Sakura Mobile port-out | ¥1,100 | Sakura Mobile |
| IIJmio, mineo port-out | Free | IIJmio, mineo |
Separately, check your old carrier’s early cancellation fee:
If you bought a phone on installments, the remaining payments keep coming from your registered card or account, SoftBank says, unless you ask to pay them in one go.
One exception matters for foreigners: Mobal says existing Japanese numbers can’t be ported in, so you’d get a new number. Sakura Mobile accepts MNP, and its SIM arrives 5 to 7 days after approval.
Before you switch, compare plans in SIM cards for foreigners, and check the ID and payment rules in our phone contract guide. The new contract needs a valid residence card like any new contract.
If you cancel, the number is gone. If you plan to come back, the three big carriers will store your number for a monthly fee:
| Carrier | Service | Monthly | Application fee | Maximum |
|---|---|---|---|---|
| docomo | 電話番号保管 | ¥440 (+¥110 for email) | ¥1,100 online, ¥4,950 shop or phone | 6 years |
| au | 一時休止 | ¥409 + universal service fee | ¥3,850 My au, ¥4,950 shop | 5 years |
| SoftBank | お預かりサービス | ¥429 | n/a | 5 years |
Things to know:
We didn’t find a similar storage service at Rakuten Mobile or the low-cost brands. If you’re leaving for good, cancel instead: SoftBank accepts a foreign passport alone for cancellation once you’ve handed in your residence card at departure.
Leaving Japan also affects your money. If you paid into the national pension, read about the pension refund.
Yes. The Ministry of Internal Affairs and Communications (総務省) says the MNP fee is free. Only a reservation number issued in person or by phone can cost up to ¥1,000 plus tax. Your new carrier may charge a contract fee, and your old one may charge an early cancellation fee.
MNP予約番号 is the code your current carrier gives you so the new carrier can move your number. ahamo says it is valid for 15 days including the day it's issued, and ahamo wants at least 10 days left when you apply. You don't need one if both carriers support one-stop MNP.
No. Mobal says existing Japanese numbers can't be ported in, so you would get a new number. Sakura Mobile accepts MNP.
Yes, with docomo, au or SoftBank. docomo stores it for ¥440 a month for up to 6 years, au for ¥409 a month for up to 5 years, and SoftBank for ¥429 a month for up to 5 years. When the period ends, the contract is canceled and the number is lost.
With one-stop MNP you finish the switch on the new carrier's website, and the old contract ends automatically when the line switches. If a SIM has to be posted, add delivery time: Sakura Mobile says its SIM arrives 5 to 7 days after approval.
Spotted something out of date or wrong? Email hello@japanhow.com and we will check it against the source. See our corrections policy.
Photo: James Nash / CC BY-SA 2.0
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