[Japan Travel eSIM] The Pitfall of "Unlimited"? A Complete Guide to Fair Usage Policy (FUP)

eSIM is essential for a comfortable trip to Japan. Plans labeled as "unlimited data" are especially attractive. However, did you know that unlimited eSIMs provided in Japan are always subject to a **Fair Usage Policy (FUP)**? This policy means that high-speed data is, in many cases, not truly unlimited.

This article will clearly explain everything travelers should know about the FUP for Japan-bound eSIMs. Here are two important points you must confirm before purchasing:

• Specific speed restriction conditions: How much data (per day or in total) can be used before speed restrictions are applied.
• Restriction removal timing: Will the restricted speed be reset the next day, or will it be lifted after a certain period of time?

[Reality Check] Why 1GB to 2GB of Data Per Day is Often Sufficient for Travelers

While many travelers seek unlimited data eSIMs, the reality is that for most users, 1GB of data per day is enough for basic smartphone needs. If your main uses are map apps, social media, and simple web searches, 1GB per day is usually sufficient. Even if you frequently watch videos, a plan that allows about 2GB of data per day will enable most users to enjoy data services comfortably without worrying about speed restrictions.
Having the ability to communicate with unlimited data is reassuring, but it's helpful to understand that you will likely not need more than 2GB at most.

What Travelers Should Know! 5 Reasons Why FUP is Applied in Japan

1. To Maintain Network Quality and Stability

Telecommunication companies share a limited bandwidth among tens of thousands of users. If a small number of users continuously consume a large amount of data without interruption, it can overload the entire network and reduce the communication speed for the majority of other users. FUP is designed to prevent this "collective collapse" and provide a comfortable communication environment for everyone.

2. To Prevent Over-Occupation by Some Heavy Users

The term "unlimited" can lead to a small number of users engaging in excessive data usage (e.g., long-term high-definition streaming, continuous downloading of large files). FUP ensures a fair balance of data usage between heavy users and general users by temporarily limiting the speed of users who exceed a certain data amount.

3. To Keep Telecommunication Infrastructure Costs Manageable

Operating and maintaining telecommunication infrastructure, such as base stations and network equipment, involves enormous costs. If truly unlimited plans were offered and data usage continued to increase indefinitely, constant infrastructure upgrades and maintenance would be required, ultimately leading to higher service prices. FUP is a rational mechanism for controlling excessive use and managing costs.

4. To Provide Fair Service to All Users

FUP, behind the promise of "unlimited," guarantees that all users can enjoy a stable communication environment. By setting speed limits for users who exceed certain thresholds, it helps ensure that other users can maintain a good quality of service.

5. To Deter Illegal and Inappropriate Data Use

Extreme data consumption by some heavy users may be related to inappropriate network activities, such as illegal downloading, commercial resale, or unauthorized server operation. Applying FUP helps discourage these unhealthy behaviors and promotes the responsible use of the network.

[Important] How FUP Works: Specific Data Restrictions and User Experience

Specific Examples of FUP Data Restrictions

Many Japan-bound eSIM services apply FUP in the following way:
Example: "If you use more than 5GB per day or a total of 100GB over 30 days, the communication speed will be restricted to a maximum of 1Mbps until 〇 AM the next day."
In this way, FUP acts as a "hidden limit" for comfortable service use. Be sure to check both the **daily limit** and the **total limit (monthly limit)** before purchasing.

In many cases, data usage will be restricted if you use your smartphone's tethering function for communication on other devices.

What Can You Do with a Restricted Speed (1Mbps or 128Kbps)?

If speed restrictions are applied, practical usability significantly decreases.

• For a maximum of 1Mbps: Website loading will be slow, but map app location display, text messages (like LINE), and low-quality YouTube viewing (with potential interruptions) are barely possible.
• For a maximum of 128Kbps: Most websites take a long time to load, and practically, you are limited to sending and receiving text messages. Comfortable use is extremely difficult.

[Must-See for Tethering Users] The Advantage of Choosing an eSIM Plan with Clear FUP and High Capacity

Tethering (hotspot use) is a usage method where data consumption increases rapidly, making it a common reason for FUP restrictions on many unlimited eSIM plans. Especially among plans claiming to be "unlimited," there are often cases where speed is restricted via the terms of service when tethering is used. If you plan to use your smartphone as a hotspot, it is crucial to check the restrictions on tethering before purchasing an unlimited plan.

The eSIM we provide offers a high-capacity "3GB per day" plan without tethering restrictions, catering to users who seek truly "unlimited" usage.
The key difference from other services is that within the 3GB daily limit, there are no additional restrictions when using your smartphone as a hotspot to connect PCs or tablets. This allows for comfortable simultaneous connection of multiple devices.
Even if you exceed 3GB, the communication speed will automatically recover the next day, so you can rest assured.
If you are looking for an eSIM plan with large capacity and the freedom to use tethering, please consider our eSIM. UNLIMITED DATA eSIM Japan