Unfortunately, it is not possible to directly change a Data-only plan to a Monthly Voice+Data plan, or vice versa.
Since they are separate products, you will have to place a new order for the product you wish to switch to.
If you are looking to only change your SIM type (SIM ⇆ eSIM), please view the following article:
FAQ: I want to change the type of SIM I have (SIM card ⇆ eSIM)
Overview:
1. Terminate your current contract (if no longer needed)
2. Place an order for the product you wish for instead
The image below is a simple visualization of the process that you need to go through.
Order timing
Since all of our contracts can only be terminated at the end of each month, and we do not prorate the final month's fees, we recommend customers begin their new contract at the end of the month.
For example: If you terminate your Data-only plan for the end of January and begin your new Monthly Voice+Data plan on January 30th, your January bills will be as follows: Full month's usage fee (Data-only) + 2-day prorated fee (Monthly Voice+Data)
Termination process
The deadline to terminate at the end of a given month is the 25th of that month.
Please submit the termination request online through your Sakura Mobile My Page by this deadline.
FAQ: How do I cancel/terminate my Monthly contract?
※The last bill of your old contract will be invoiced and charged one month after termination.
New order discount
In consideration of customers who are ordering with us again, we are able to offer an exclusive discount on the registration fee of your new order if you are switching from another type of contract.
To receive this discount, please contact us and we will provide further instructions.
For cash payment (Smart Pit) customers
The deposit amount required for Monthly Voice+Data plans paid via cash is 20,000 JPY.
FAQ: What is the deposit? Why is it necessary?
This is an estimated amount due to the fact that calling/SMS fees are calculated on a usage basis, which will not be determined until the end of each month. Rest assured, if there is leftover after the last two months' bills are paid, we will refund you the remaining amount.
The deposit is not eligible for the discount mentioned above, which only applies to the registration fee.
