If you are looking for information on Fair Usage Policy (FUP) for the Unlimited Travel SIM Card, please read here: https://support.sakuramobile.jp/hc/en-us/articles/360020266412-I-am-confused-about-unlimited-data-What-does-unlimited-data-service-mean-
Our company does its best to provide our customers with large amounts of data that they can comfortably use while in Japan. However, there is a policy that is enforced by network carriers to provide equal and fair usage for individuals on the mobile network.
Essentially, all pocket WiFi "Unlimited" plans offered in Japan have a Fair Usage Policy (FUP). This is a policy that mobile carriers in Japan have to help keep the network stable for all users on the network. To keep the network and data usage equal among all users, individuals who are using large amounts of data over certain periods of time may have their speeds restricted. Below, you will find the FUP for the current Unlimited plan offered by Sakura Mobile.
FUP (Fair Usage Policy):
※ 10GB / 3 days (Whether you will be on FUP tomorrow from 6:00 PM to 2:00 AM will depend on the total usage of today, yesterday and the day before is over 10GB or not)
※ The speed at the time of FUP going into effect: Maximum 1 Mbps (Limited only from 6:00 PM to 2:00 AM. You can use it without restrictions during other times.)
※ Although there is a FUP, you are still able to use the internet and data at normal speeds during the hours of 2 AM - 6 PM, regardless of whether you have the FUP in effect on your device.
The number on the main screen of the device shows the amount of data that has been used over the most recent 3 days.
Case ①: If you use a total of 9.9GB on day 1, 2, and 3, the speed will be kept as high speed on day 4.
Case ②: If you use a total of 36.6GB on day 2, 3, and 4, the speed will be restricted on day 5, but ONLY between 6:00 PM to 2:00 AM.
Case ③: If you use a total of 35.6GB on day 3, 4, and 5, the speed will be restricted on day 6, but ONLY between 6:00 PM to 2:00 AM.
Case ④: If you use a total of 35.3GB on day 4, 5, and 6, the speed will be restricted on day 7, but ONLY between 6:00 PM to 2:00 AM.
Case ➄: If you use a total of 8.3GB on day 5, 6, and 7, the speed will be kept as high speed on day 8.