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SoftBank to Y!mobile: online transfer guide ​

A guide for transferring your mobile line from SoftBank to Y!mobile online, including procedures, costs, and tips.

Overview ​

The move from SoftBank to Y!mobile is handled not as a general "MNP to another carrier" (他社MNP), but as a "number transfer" (番号移行) within the SoftBank group. You do not need to obtain an MNP reservation number (MNP予約番号). Y!mobile's official guidance states that, for number transfers from SoftBank or LINEMO, issuance of an MNP reservation number is not required. After the application is completed with Y!mobile, SoftBank automatically cancels the old line.

If proceeding online only, the overall flow is:

  1. advance confirmation
  2. Y!mobile online application
  3. receipt of SIM or eSIM and line switching
  4. initial setup
  5. confirmation of discount application and benefits.

eSIM can start as early as the same day, and a SIM card can ship as early as the same day.

Procedures (online only) ​

Advance confirmation ​

Confirm device compatibility Check the Y!mobile supported devices page (動作確認端末) to see whether the device you plan to keep using works with Y!mobile SIM or eSIM. If you want eSIM, the device must support eSIM, and you need a Wi-Fi connection during initial setup.

Confirm SIM lock status Many recent devices do not have a SIM lock. For an older SoftBank device, confirm just in case. Y!mobile provides guidance for SIM unlock (SIMロック解除) when using a device from another carrier.

Confirm contract information On the SoftBank side, confirm any remaining installment balance, whether there is proration, and the impact of ending discounts. SoftBank officially states that device installment balances continue after cancellation, that the cancellation month is generally not prorated, and that discounts may end.

MNP reservation number ​

Obtaining one is unnecessary in this case For SoftBank to Y!mobile transfers, because it is a number transfer (番号移行), an MNP reservation number is not necessary. Y!mobile's application procedure page confirms this. The online application guide also indicates that identity verification documents (本人確認書類) may be unnecessary for number transfers from SoftBank.

Items to confirm beforehand If there is a mismatch in contract holder name, unpaid amounts, a special contract, a corporate contract, or certain device conditions, the process may not proceed as usual. Y!mobile states that the procedure cannot be completed if payment confirmation cannot be made.

Y!mobile online application ​

Apply through the official Y!mobile online store

  1. Go to the Y!mobile official online store.
  2. Select 今の電話番号をそのまま使用 then SoftBank/LINEMOからのりかえ then SIMのみ申し込む. The basic flow is: plan and option selection, identity verification, information entry, confirmation of agreement, and application completion.

Choose SIM or eSIM

  • eSIM: Service can start as early as the same day. Best for people who want to switch immediately. Wi-Fi is required.
  • SIM card: Can ship as early as the same day. Setup is easier to understand, and it is easier to recover if trouble occurs.

Practical recommendation:

  • If you want immediate activation and have eSIM experience - choose eSIM
  • If you do not want to risk failing setup, or are concerned about device compatibility - choose SIM card

Set the payment method If you set PayPay Card Gold as the payment method, you become eligible for Y!mobile's PayPayカード割 (PayPay Card Discount). Under シンプル3 (Simple 3) from September 25, 2025 onward, PayPay Card receives JPY 330 off per month, and PayPay Card Gold receives JPY 550 off per month.

Activation and initial setup ​

SIM card activation After the product arrives, perform line switching (回線切替) yourself. According to Y!mobile's application flow page, the switching desk reception hours are 9:00-21:00. If you do not switch by 21:00 on the sixth day from the product arrival date, it switches automatically on the seventh day.

eSIM activation According to Y!mobile's eSIM flow page, switching completes in about 15 minutes after the procedure. Line switching reception hours are 9:00-21:00.

APN and profile settings On iPhone, the process is likely to proceed automatically, but depending on the device, APN settings may be necessary. For eSIM, this means a profile download. For a SIM card, replace the card and confirm connectivity. Y!mobile also provides a communications settings page for SIM-free iPhone and iPad devices.

After switching ​

Confirm and apply for おうち割 光セット（A） If you will continue SoftBank Hikari, switch on the Y!mobile side to おうち割 光セット（A）. Y!mobile states that there is a monthly discount when Y!mobile lines are contracted together with SoftBank Hikari, SoftBank Air, and similar services. The online store guide also explains the application method for those already under contract for SoftBank Hikari.

Reconfirm PayPay and PayPay Card linkage According to PayPay Card's benefit page, to receive benefits you need to confirm SoftBank linkage settings, set PayPay Card as the payment method for smartphone charges, and if necessary, set up combined billing for Hikari and electricity.

Cost breakdown ​

  • SoftBank MNP transfer-out fee: JPY 0. Clearly stated in SoftBank's official FAQ.
  • SoftBank contract cancellation fee: In principle, JPY 0. Since February 1, 2022, many consumer rate plans are exempt even outside the renewal month. There are exceptions for some corporate plans and fixed communications services. See SoftBank's cancellation fee FAQ.
  • Y!mobile online contract administrative fee: JPY 3,850 (tax included). In-store is JPY 4,950; online is JPY 3,850.
  • SIM issuance fee: No separately charged SIM issuance fee was confirmed in official information. The main cost at the time of initial contract is the contract administrative fee.
  • eSIM reissuance fee: If eSIM is reissued after contract, a fee may arise, but eSIM reissuance from My Y!mobile is free. For in-store procedures, an administrative fee may be required.
  • Remaining device balance: If installment payments for the device remain, payment continues even after SoftBank cancellation.
  • SoftBank charges for the cancellation month: Except in some cases, the full amount is billed with no proration.

Estimated total cost ​

Assuming there is no remaining device balance or exceptional cancellation fee, the effective initial cost is mainly the Y!mobile online contract administrative fee of JPY 3,850 (tax included). If cancellation is made mid-month, SoftBank's final month is billed in full, and Y!mobile's monthly service charge is added.

https://www.ymobile.jp/store/sp/sim/#

Impact on existing services ​

Changes to PayPay Card Gold benefits ​

  • The card itself can continue to be used. Canceling SoftBank does not make the card invalid.
  • The benefits change from SoftBank-oriented to Y!mobile-oriented. PayPay Card's official information confirms benefits with Y!mobile when set as the payment method for communications charges.
  • Under Y!mobile シンプル3 (Simple 3) from September 25, 2025 onward, PayPayカード割 is JPY 330/month for PayPay Card and JPY 550/month for PayPay Card Gold.
  • According to PayPay Card's benefit explanation, the point grant rate for smartphone communication charges under シンプル3 appears to be up to 1% even for PayPay Card Gold. Do not assume a "10%" figure from past promotions applies to シンプル3.

Impact on SoftBank Hikari bundle discount ​

  • SoftBank Hikari itself is not automatically canceled when the mobile line moves.
  • The おうち割 光セット on the SoftBank mobile side ends when the mobile contract is canceled. SoftBank's cancellation notes page states that discounts may end with cancellation or number transfer.
  • You can switch on the Y!mobile side to おうち割 光セット（A）. Y!mobile's bundle discount page confirms that Y!mobile lines receive discounts when bundled with SoftBank Hikari, SoftBank Air, and similar services.
  • For シンプル3 S, official pages show a JPY 1,100/month discount (tax included), while another simulation shows JPY 1,650/month (tax included) for おうち割 光セット（A）. Because the display context differs, confirm the final amount on the application screen or fee simulation. At minimum, you can replace the SoftBank-side bundle discount with the Y!mobile-side bundle discount while maintaining SoftBank Hikari.

Alternative discounts with Y!mobile ​

  • おうち割 光セット（A）
  • PayPayカード割
  • 家族割引サービス (Family Discount Service), depending on conditions

Y!mobile officially states that 家族割引サービス and おうち割 光セット（A） cannot be combined.

Campaigns and discounts (online) ​

Confirmed benefits currently available ​

  • SIM/eSIM contract benefit on Y!mobile official online store: In the official campaign list, up to the equivalent of JPY 15,000 in PayPay points may be presented for SIM card or eSIM contracts.
  • PayPay point benefit at the time of SIM/eSIM contract: The official SIM page also indicates a PayPay point code present as an eSIM/SIM contract benefit.
  • PayPayカード割: Under シンプル3 from September 25, 2025 onward, JPY 330/month off for PayPay Card and JPY 550/month off for PayPay Card Gold. This is a standing discount, not a campaign.
  • Benefits related to おうち割 光セット（A）: Y!mobile has pages for campaigns related to joining おうち割 光セット（A）, and under certain conditions benefits are granted. Some pages include conditions that require in-store application, so the same conditions may not apply for online-only applications. Confirm eligibility for each application route.

What is realistically achievable ​

  1. Online application benefit for SIM/eSIM
  2. JPY 550 monthly discount for PayPay Card Gold
  3. Y!mobile-side おうち割 光セット（A） by continuing SoftBank Hikari

Layering these three is realistic in an online transfer.

Recommendations and advice ​

Safest way to proceed ​

If this is your first time, a SIM card is recommended. If you are familiar with eSIM, choose eSIM.

eSIM is fast, but Wi-Fi is required. If you run into trouble during eSIM setup, recovery is difficult. A SIM card requires waiting for delivery, but it is less likely to fail.

Timing to minimize cost ​

Switching near the end of the month tends to be advantageous. SoftBank charges the full amount for the cancellation month with no proration in most cases. On the Y!mobile side, there is guidance on prorated discounts for the contract month, and the activation timing for SIM/eSIM is easy to adjust yourself. As a general rule, aim for several days before month-end through month-end. This recommendation is based on official proration rules.

How to preserve bundle discounts ​

There is no need to stop SoftBank Hikari. Leave SoftBank Hikari as it is, move only the mobile line to Y!mobile, and apply for おうち割 光セット（A） on the Y!mobile side. This lets you continue receiving the bundle discount without any switching construction work for the fixed line.

Important checks at the time of application ​

  • Select number transfer from SoftBank
  • Set PayPay Card Gold as the payment method
  • Keep SoftBank Hikari contract information at hand
  • Apply from the campaign-eligible page

The last point is important because Y!mobile's applicable conditions differ by campaign page. If you enter from the normal application route, you may become ineligible for the benefit.

Confirmed information vs. items requiring confirmation ​

Confirmed information:

  • MNP reservation number is unnecessary
  • SoftBank transfer-out fee is JPY 0
  • Cancellation fee is generally JPY 0
  • Y!mobile online administrative fee is JPY 3,850
  • eSIM can start as early as the same day
  • SIM card can ship as early as the same day
  • SoftBank cancellation month is generally not prorated

Items requiring confirmation:

  • The final billed amount under your current SoftBank plan
  • Whether there is any remaining device balance
  • The final discount amount for Y!mobile-side おうち割 光セット（A）
  • The campaign amount at the time of application

These require individual confirmation on the application screen or in My SoftBank.

Reference information ​