With more travelers turning to eSIMs to stay connected in Japan, there’s also a growing number of eSIM plans claiming to offer “unlimited” data. But what does unlimited really mean?
In many cases, unlimited plans come with hidden limits, like daily data caps.
In this guide, we’ll break down the differences between eSIMs with FUP (daily caps) and truly unlimited data eSIMs, helping you find the right option for your needs.
Table of Contents
1) What is an eSIM and Why Use One in Japan?
2) “Unlimited” Data in Japan – What’s the Catch?
Unlimited with FUP (Fair Usage Policy)
3) Why FUP Plans Can Still Work for Travelers
4) What Truly Unlimited Looks Like
5) Introducing Sakura Mobile’s Unlimited 5G eSIM – No FUP, No Limits
6) How to Choose the Right Unlimited eSIM for Your Trip
7) Conclusion
With Sakura Mobile’s new 5G unlimited eSIM, you’ll get fast, stress-free data in Japan – no limits, no throttling.
What is an eSIM and Why Use One in Japan?
An eSIM (embedded SIM) is a digital version of a physical SIM card. Instead of swapping out a physical card, you can activate a mobile plan by scanning a QR code – simple as that.
Why Travelers Love eSIMs:
✅ No SIM swapping – Keep your SIM safe and avoid the hassle of swapping or losing physical cards.
✅ Instant connection – Stay online from the moment you touch down with automatic activation.
✅ Dual SIM flexibility – Keep your home number/plan and use a local eSIM for travel.
Whether you’re finding your way through train stations, translating menus, or posting your trip highlights, eSIMs make it easier than ever to get connected the moment you land.
💡Tip: A foreign eSIM uses international roaming, which can mean slower speeds. But a local eSIM connects directly to Japanese networks for faster, more reliable data—perfect for travel in Japan!
Check out our guide to Foreign vs. Local Japan eSIMs to learn more!
Japan “Unlimited” Data – What’s the Catch?
Although many Japan eSIM plans promise unlimited data, the reality is that “unlimited” often comes with fine print—like speed caps or daily limits.
Plans with a Fair Usage Policy (FUP) give you a certain amount of high-speed data per day, then slow things down once you hit the cap. Let’s break down the different unlimited options below.
Truly Unlimited Data Plans
A truly unlimited eSIM gives you unrestricted access to mobile data. This means:
✅No daily high-speed data limits
✅No throttling
✅No Fair Usage Policy (FUP)
These plans are less common among travel eSIM providers in Japan. But don’t worry, we’ll introduce one that delivers truly unlimited data later in the article.
Unlimited with FUP (Fair Usage Policy)
This is the most common type of unlimited plan in Japan.
Here’s how it usually works:
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- You get a certain amount of high-speed data per day (ex. 2 GB).
- Exceed your limit, and your speeds will drop (128 kbps ~ 200 kbps).
- Speeds will be too slow for video calls, uploads, or fast browsing.
- You’ll still have mobile data, just not unlimited high-speed data.
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The short answer is that Fair Usage Policies help manage network traffic to keep service stable for all users. But if you rely heavily on your phone while traveling, these limits can quickly become frustrating.
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Why FUP Plans Can Still Work for Travelers
So, if FUP plans come with limits, why are they still so common in Japan?
The answer is simple: for many travelers, 2 GB or 3GB a day of high-speed data is more than enough.
FUP-limited eSIMs may be an option if:
- You’re on a short trip and plan to supplement with free WiFi at hotels or cafés
- You mostly use your phone for maps, messaging, and light browsing
- You don’t plan on uploading a lot of content or streaming
Still unsure if that’s enough data for your needs? Here’s an estimate of how much data you’ll use:
- Google Maps & messaging: ~500–800 MB/day
- Browsing & social media: ~800 MB–1.5 GB/day
- Streaming videos: ~1–3 GB/day
Another point to keep in mind: FUP-based plans typically cost less than truly unlimited options, making them a possible alternative for budget travelers.
👉 Check eSIM compatibility
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What Truly Unlimited Looks Like
As we’ve covered, most unlimited data eSIMs in Japan come with daily data limits. But a truly unlimited eSIM gives you full-speed access with no FUP, no slowdowns, and no daily caps—so you can stream, navigate, and video call without interruption.
This kind of plan is ideal if you:
- Use Google Maps or translation apps frequently
- Make video calls or stream YouTube/Netflix
- Post lots of photos and videos to social media
- Use your phone as a hotspot
If you’re tired of hitting daily caps, you’ll be happy to know that there is a better option!⬇️
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Introducing Sakura Mobile’s Unlimited 5G eSIM – No FUP, No Limits🌸
With a truly unlimited data plan, you can forget about managing data usage altogether.
That’s why Sakura Mobile’s truly unlimited 5G eSIM is perfect for letting you focus on enjoying your trip in Japan.
Features:
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- 🚀Truly unlimited 5G data – No FUP = no daily limits, no slowdowns, no stress
- 📶 Powered by the au Network – Enjoy fast, reliable coverage across Japan
- 😊Worry-free travel – No need to monitor usage or top up data
- 🌍Instant connection – Just pre-order online and scan a QR code to get started
- 🏞️Designed for travelers to Japan – Navigate, share, and stream without limits
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Stay connected effortlessly, enjoy Japan to the fullest, and focus on making memories, not managing data.
Pre-order now and enjoy seamless, high-speed data from the moment you arrive.
How to Choose the Right Japan Unlimited eSIM for Your Trip
Not sure which type of eSIM you need? Ask yourself:
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- How long are you staying in Japan?
- How much data do you use daily?
- Will you be making video calls or streaming?
- Do you want zero slowdowns or just basic connectivity?
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We recommend a truly unlimited 5G eSIM if:
• You don’t want to worry about managing your data (no daily limits!)
• You value fast speeds and 5G performance
Consider our Unlimited 4G eSIM/SIM if:
• You want an affordable option for general browsing and maps
• You don’t need 5G as long as you have 4G LTE speeds
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Conclusion
“Unlimited” doesn’t always mean unlimited – especially in Japan. With many eSIMs, you’ll face data speed reductions after hitting a cap, even though you’re technically still connected.
If you want freedom, reliability, and peace of mind, go with a truly unlimited data eSIM.
✅ No FUP (data caps)
✅ No slowdowns
✅ No stress
Get Your 5G Unlimited Data eSIM for Japan Now – Fast, Reliable, No Throttling
Install before your trip so you can land connected!
