To get to your "Manage Plan" page, please follow the directions below.

First, please log in to your [Sakura Mobile My Page] 
LINK: https://myaccount.sakuramobile.jp/auth/login

※If this is your first time logging into your [Sakura Mobile My Page], please visit here

1) Select the contract you would like to manage 

2) Select "Contract details"

3) Continue to select the product you would like to manage

4) You will then be able to see the Manage Plan page.