You can apply to cancel the service at the end of the month through the [Sakura Mobile My Page]  by the 25th of every month. (After the initial 3-months usage has passed.)

If submitted by the 25th, the contract will then end at the end of that month.
If the 25th has passed, the contract will be canceled at the end of the following month.

After canceling the contract, you will need to return the rental equipment (home gateway device or ONU modem and included accessories).

Below is the link to the [Sakura Mobile My Page] 

Sakura Mobile My Page

Steps to submit the Termination Form

1) Log in to your [Sakura Mobile My Page]

2) Go to the "Manage Plan" page for your plan you would like to terminate
For information on how to get to your "Manage Plan" page, visit here.

3) Select "Terminate Contract" 

4) Select "Cancel Contract"

5) Fill in the required information

6) Check that the information automatically filled in is correct. (*)
Please select the date of departure if you are leaving Japan.

7) Submit the form

※If you are logging into the [Sakura Mobile My Page]  for the first time, please follow the instructions in the link below.

How do I log into [Sakura Mobile My Page] for the first time?