Daily Life Lessons · Mobile Phones
When cancelling or switching mobile phone carriers, be able to check how to keep your phone number (MNP), fees, cancellation charges and the remaining device payments, prepare by making backups, and then proceed with the procedure yourself.
Even if you change mobile carriers, you can keep your current phone number by using "MNP" (番号ポータビリティ, mobile number portability). Since May 2023, a "one-stop method" (ワンストップ方式) has also been available, which lets you complete the procedure just on the new carrier's website (some companies do not support it). If you apply online, the transfer-out fee charged by your current carrier is free.
There is a cap under the rules on the cancellation fee for ending a fixed-term contract early. For carriers above a certain size, the cap is 1,100 yen or the monthly fee, whichever is lower (for contracts made from July 2022 onward). Many plans have no cancellation fee at all. If you are paying for your device in installments, you will keep being billed for the rest even after you cancel.
Before you start, back up your photos and contacts, and also check which phone number you use for SMS authentication with banks and other services.
携帯会社を 変えても、「MNP」を 使えば、今の 電話番号を そのまま 使えます。
- 新しい 会社の Webサイトだけで 手続きが できる ことも あります。 - 今の 会社に 払う 手数料（てすうりょう）は、Webで 申し込めば 無料です。 - 契約の 期間の 途中で やめる ときの お金（解約金）には、上限（じょうげん）が あります。解約金が ない プランも 多いです。 - 電話（たんまつ）の 代金が 残って いたら、やめた あとも 払います。
手続きの 前に： - 写真や 連絡先（れんらくさき）を 保存（ほぞん）する - 銀行などで 使って いる 電話番号を 確認する
What happens if you use MNP (mobile number portability)?
With MNP, you can keep using your phone number even if you change mobile carriers.
If you apply online, how much is the transfer-out fee charged by your current carrier?
If you apply online, the MNP transfer-out fee is free.
What is the "one-stop method" that started in May 2023?
You can complete the procedure just by applying on the new carrier's website. However, some companies do not support it.
What happens if you cancel while still paying for the device in installments?
Device installments continue until they are paid off, even if you cancel or switch carriers.
What is good to do before switching?
If you save your data and check the phone number you use with banks and other services, you won't have trouble later.
Q. Can I keep using my carrier email address after switching?
A. If you use a paid service called "carrier email portability" (キャリアメールの持ち運び), you may be able to keep using the same address after switching. The deadline for applying and the fee differ by company, so check your current company's website.
Q. What should I do when I return to my home country?
A. Cancel any lines you will no longer use before you leave Japan. If you still have device installments left, also ask the company you have a contract with how to pay them. You must not sell or give your mobile phone or SIM card to anyone else.
Q. I got a text message saying "Switch and get tens of thousands of yen."
A. Do not open the link in the message. Fake text messages and fake websites pretending to be mobile carriers may trick you into giving away personal information or money. Check campaigns on the mobile carrier's official website. If you are in trouble, you can call the consumer hotline "188" for advice.
This practice tool asks questions in random order (it works when JavaScript is enabled). You can still read all the questions and explanations above without it.
Systems and procedures may differ depending on the city, ward, town or village where you live and on the time of year. Please check the latest information from your local government or the relevant organizations.
Content checked on: 2026-10-03
This page is a translation of the Japanese original. If the translation and the original differ, the Japanese version takes precedence. View the Japanese original