If you plan to travel to Japan and use your T-Mobile plan, you might be excited to know that some plans offer free roaming. However, before you pack your bags and assume everything will be smooth sailing, there are some important limitations and potential pitfalls to keep in mind.
In this guide, we discuss the pros and cons of using T-Mobile in Japan and offer alternatives to help you stay connected.
Let’s get started!✨
Table of Contents
- Does T-Mobile Work in Japan?
- Go5G Next/Plus and Go5G Plans in Japan
- T-Mobile’s Data Passes in Japan
- Why Choose Sakura Mobile? Affordable and Flexible Data Options
- Maximize Your Data with These Tips
- Check This Before Your Trip
- Enjoy Your Trip to Japan!
Verizon in Japan: Comparing Plans and Cheaper SIM Options
Guide to AT&T International Plans in Japan
Mint Mobile in Japan: Comparing Passes and Local SIM Options
Does T-Mobile Work in Japan?
Good news! If you’re on T-Mobile’s Go5G Next or Go5G Plus plans, you can use T-Mobile in Japan at no extra cost. The Go5G plan is also free to use in Japan but at much slower speeds.
If you are not under these plans, you will need to buy “data passes” to use T-Mobile during your trip.
TIP: Customers under the discontinued Magenta (or Magenta MAX/Plus) and T-Mobile ONE plans can also use their phones in Japan for no extra fees. Check the T-Mobile website for more information.
⚠️Note that T-Mobile’s prepaid plans have no international options (no data roaming, cannot buy international data passes, and calls/texts have additional fees).
Before diving into connection speeds, let’s first discuss T-Mobile’s coverage in Japan. 📶
For details about the Go5G & Go5G Next/Plus plans: Click here👈
💡T-Mobile Data Passes in Japan
For more info on T-Mobile’s data passes: Click here👈
T-Mobile’s Coverage in Japan
The above map shows that you should have 4G LTE coverage under your T-Mobile plan in most of Japan. You should not have any issues getting a connection unless you are underground or in a mountainous area.
*Note that Japan uses 3G, 4G LTE, and 5G networks, meaning that 2G-only phones won’t work in Japan.
The Japanese partner network for T-Mobile is not publicly listed, but it is most likely one of Japan’s three biggest carriers: docomo, au, or SoftBank.
Next, we will break down the amount of data you get, connection speeds, and the data passes.
NOTE: Because the networks that T-Mobile uses in Japan are unclear, troubleshooting could be difficult for their support, as they may be unfamiliar with Japanese networks.
T-Mobile also has a disclaimer that they are not responsible for partner networks’ coverage, so you may run into issues if you have poor connectivity.😟
Check out Sakura Mobile’s Travel SIM/eSIM options below!👇
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Go5G Plus/Next and Go5G Plans in Japan
Wondering how your T-Mobile plan works in Japan and how it compares? Here are the details for each plan below:
Pricing💰
If you’re on a Go5G or Go5G Plus/Next plan, using mobile data and sending texts won’t cost extra. However, keep in mind that both incoming and outgoing calls will cost $0.25 per minute.
TIP: Calling to the US, Mexico, or Canada?📞 Outgoing calls over WiFi are free, but other destinations are $.25/min. We recommend using a third-party app like Facebook Messenger or LINE to make calls.
Connection Speeds⚡
- Go5G: Unlimited data up to 256 Kbps.
- Go5G Plus and Next: 5GB of high-speed data, then unlimited up to 256 Kbps
The maximum speed that you can get with the Go5G plan is 256 Kbps, which can feel quite slow.
Google Maps will most likely run slowly, and streaming videos and loading images won’t work smoothly.
With Go5G Plus and Next plans, you can use up to 5GB of high-speed data. However, the exact connection speeds are not listed on the T-Mobile website.
With international roaming, you may have lower network priority than local users with direct contracts, meaning that your speeds may vary, and you are not guaranteed 5G network speeds.
Data Amount📱
Although Go5G Plus and Next plans give you 5GB of high-speed data, whether or not this is enough depends on how much you use the internet.
The following is about how much data you will need to complete different phone activities.
- Using Google Maps and sending texts: 500MB ~ 800MB/day
- Browsing the internet and using social media: 800MB ~ 1.5GB/day
- Watching videos: 1GB ~ 3GB/day
If you plan to navigate frequently, scroll social media, or watch videos, 5GB may not last long.
Using your T-Mobile plan in Japan is not recommended for extended stays due to T-Mobile’s terms, which state that primary usage must be in the US. Your service may suddenly be terminated for excessive roaming.If you’re staying in Japan for a while, check out our long-term plans below!
Will T-Mobile’s International Roaming Plans Be Enough?
T-Mobile’s Go5G and Go5G Plus/Next plans might work for some travelers, but others may feel limited by the slow speeds and 5GB high-speed data cap. Here’s who these plans are best suited for:
Go5G:
🔸Light data users who don’t mind slow speeds
🔸Don’t need to check Google Maps constantly
🔸Staying in Japan for a short time (1 week)
Go5G Plus/Next:
🔹Can survive on only 5GB of high-speed data
🔹Don’t plan on streaming/watching videos
🔹Staying in Japan for a short time (1 week)
Most travelers stay in Japan for at least a week. To make your 5GB last the entire trip, you should expect only to use Google Maps and send texts.
If you run out of data, T-Mobile does offer data passes for extra high-speed data—more on that in the next section!
Check out the article below for the best Japanese SIM card and eSIM in 2025!
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T-Mobile’s Data Passes in Japan
For those who do not have a Go5G or Go5G Plus/Next plan, you will need to purchase data passes in order to use T-Mobile while in Japan.
Even if you do have a Go5G Plus/Next plan, you might run out of your 5GB of high-speed data. In that case, you can also buy a data pass to stay connected at faster speeds.
Check out the three types of data passes below.👇
Scroll right for more (on mobile)→→
| 1 Day International Pass | 10 Day International Pass | 30 Day International Pass |
|
| Cost | $5 | $35 | $50 |
| Data Cap | 512MB | 5GB | 15GB |
| Usage Period | 24 hours | 10 days | 30 days |
✅ Unlimited calling in 215+ destinations (Japan included)
✅ Mobile hotspot is available
⚠️Limited to 2 passes per 24 hours
⚠️Speed after data runs out:
🔹Go5G & Go5G Plus/Next: Drops to 256 Kbps
🔹Essentials Plan/other eligible plans*: Drops to 128 Kbps
(Other plans include Magenta, ONE, or Simple Choice.)
Are these data passes worth it? 🤔 Before purchasing, let’s discuss what you need to consider in the next section!
Allocated Data
The data passes offer flexible options with no set daily data limits. There is only an expiration date (24 hours, 10 days, or 30 days). But what happens if you’re unsure how much data you’ll use?
If any of the following sound familiar, buying extra data passes could end up being more expensive than you think:
🍜You want to search for great restaurants nearby
📸You love sharing pictures on social media
🎬You want to watch YouTube videos or Netflix
Once you’ve used up your data allowance, your connection speeds will drop to a maximum of 128 Kbps or 256 Kbps (based on your plan), which will not allow you to do much of anything.
At that point, you’ll need to buy another data pass, and the costs can add up.
How Fast is the “High-Speed Data”?⏱️
While data passes can help get you back to normal speeds, keep in mind that even with a pass, you’re not guaranteed 5G service while in Japan. “High speed” means speeds above 128 Kbps/256 Kbps (after you’ve hit your data limit).
In reality, you’ll likely experience 4G LTE or slower speeds when roaming (exact speeds are not listed on T-Mobile’s site).
While buying additional passes can be convenient when you need more data, it can also become a hassle if you don’t want to worry about topping up constantly while exploring Japan.
Who Should Buy T-Mobile Data Passes for Japan?
Taking into account all the above points, these are the types of people to whom we can and cannot recommend T-Mobile data passes.
Recommended for:
✅Those who are fine with just using Google Maps and light web browsing
✅Those who want to make phone calls without WiFi
✅Those who have Go 5G Plus/Next and want to supplement their 5GB allowance
NOT recommended for:
❌Those who want to stream videos or watch YouTube
❌Those who want to share their trip on social media
❌Those who will stay in Japan for more than 1 week
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Why Choose Sakura Mobile? Affordable and Flexible Data Options
We understand that everyone’s data needs differ, and you have much to plan for your Japan trip. If you want a simple and reliable SIM/eSIM for Japan travel, we recommend Sakura Mobile as the best option.
Best Use Cases ☑️
✔️I want to use my phone without worrying about or managing my data usage
✔️I need speeds fast enough to let me watch YouTube videos or stream without any issues
✔️I am a heavy data user and plan on uploading a lot of content to social media
If any of the above apply to you, we recommend buying a prepaid SIM card/eSIM meant for traveling in Japan.
✅ Unlimited data plans from 3,500 JPY* (FUP applies)
✅ Fast, stable docomo 4G network (99% coverage)
✅ Hassle-free pickup at any international airport in Japan
✅ English support year-round
Coverage That Works Everywhere 🌍
T-Mobile relies on partner networks, which may mean patchy service or slower speeds in some areas. Sakura Mobile runs directly on docomo’s network (99% coverage), ensuring reliable service in cities, small towns, and even remote spots.
Japan-Based Support🌸
If you have issues with T-Mobile in Japan, you’re stuck dealing with U.S.-based customer service. With Sakura Mobile, you get year-round English support from a team that understands Japan’s networks.
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Maximize Your Data with These Tips
Traveling with limited data? Here are some simple ways to save data and make the most of your connection:
Check This Before Your Trip📋
Is your phone compatible with Japanese frequency bands?📱
Before heading to Japan, it’s essential to check if your phone is compatible with the country’s frequency bands.
To ensure compatibility with Sakura Mobile, you can check your device against our compatibility list:
If your device isn’t listed, don’t worry! Our customer support team is here to help. Just reach out with your questions, and we’ll get back to you by the next day.
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Enjoy Your Trip to Japan!
With so many different foods to taste and places to visit during your trip to Japan, your phone not working should be the last thing on your mind.
WiFi hopping is also not guaranteed, especially depending on where in Japan you are traveling. The networks are not always secured, especially when using a WiFi source available to the public with no password required.
We recommend getting Sakura Mobile’s Travel SIM/eSIM to be as safe as possible and enjoy your trip to the fullest.
Ready to Stay Connected?🌸
Try Sakura Mobile’s Unlimited Data SIM/eSIM!
For a stress-free and affordable option, consider Sakura Mobile. You can order an unlimited data* eSIM/SIM card online, pick it up at the airport, or deliver it straight to your hotel.
Stay connected effortlessly, enjoy Japan to the fullest, and focus on making memories, not managing data. Enjoy your trip to Japan without stressing about data passes!
Note: *FUP applies. The high-speed data available is a daily average of around 2 GB for the travel SIM card and 3 GB for eSIM. If usage exceeds this, speeds may drop.
Verizon in Japan: Comparing Plans and Cheaper SIM Options
Guide to AT&T International Plans in Japan
Mint Mobile in Japan: Comparing Passes and Local SIM Options