During a 21-day (approximately 3 weeks) trip to Japan, many travelers not only visit Tokyo, Kyoto, and Osaka but also explore Hokkaido, Kyushu, and Okinawa, or plan for workations and long stays.
The longer the stay, the more opportunities there are to use Google Maps, transit apps, translation apps, social media, video streaming, and online meetings, making it important to choose a data plan that matches the length of the trip.
If you primarily use maps and LINE, around 20GB is sufficient; if you use social media and post photos daily, around 30GB is recommended; and if you frequently watch videos or use tethering, an unlimited plan is advisable.
In this article, we will explain in detail the necessary data capacity for a 21-day trip to Japan, recommended plans based on usage style, ways to save on data usage, and how to choose a Japan eSIM.
For those who want to know more about Japan eSIM, please also check out the Complete Guide to Japan eSIM .
How many GB do you need for a 21-day trip to Japan?
Since the travel period is long, it is important to consider not only the daily data usage but also the total data capacity.
| Usage Style | Estimated for 21 Days | Recommended Capacity |
|---|---|---|
| Google Maps & LINE focused | 8–12GB | 20GB |
| Daily use of SNS & searches | 15–25GB | 30GB |
| Includes video streaming | 30–50GB | 50GB or Unlimited |
| Work & Tethering usage | 50GB or more | Unlimited |
Even if you use hotel Wi-Fi, data usage can increase during a 3-week trip, so having more than 20GB is reassuring.
For those who want to enjoy posting photos and watching videos daily, we recommend having more than 30GB.
For detailed data usage estimates, please refer to Data Usage Estimates .
How much GB can you use per day for 21 days?
By calculating the daily usage, it becomes easier to choose the necessary capacity.
| Per Day | Total for 21 Days | Recommended Capacity |
|---|---|---|
| 500MB | About 10.5GB | 20GB |
| 1GB | About 21GB | 30GB |
| 1.5GB | About 31.5GB | 30–50GB |
| 2GB | About 42GB | 50GB |
| 3GB or more | 63GB or more | Unlimited |
For example, if you focus on Google Maps and LINE, you might be able to use around 500MB per day.
On the other hand, if you use Instagram, TikTok, and YouTube daily, it is not uncommon to use around 1 to 2GB per day.
Recommended data capacity by purpose
Google Maps & Transit Apps
You will use Google Maps and transit apps daily to move to tourist spots, but the data usage is relatively low.
LINE & WhatsApp
If you mainly send text messages, the data usage is not that high.
However, if you frequently use video calls, the data usage will increase.
Instagram, Facebook & TikTok
Posting photos and viewing short videos consumes a lot of data.
If you use these daily, we recommend having more than 30GB.
YouTube & Netflix
For those who want to enjoy watching videos daily, choosing a plan with 50GB or unlimited is reassuring.
Tethering
If you connect a computer to work, the data usage will significantly increase.
For workations or long business trips, an unlimited plan is recommended.
Model Itinerary for a 21-day trip to Japan
| Travel Period | Main Stay Location | Usage Scene |
|---|---|---|
| Days 1–5 | Tokyo | Maps, Transit Apps, SNS |
| Days 6–9 | Mount Fuji & Hakone | Photo Posting, Sightseeing Searches |
| Days 10–14 | Kyoto & Nara | Translation, Hotel Searches |
| Days 15–18 | Osaka & Kobe | SNS, Video Streaming |
| Days 19–21 | Fukuoka, Hokkaido, Return | Flight Information, Maps, Communication |
During a 3-week trip, the time spent using a smartphone for intercity travel and searching for accommodations will increase.
Therefore, to avoid running out of capacity, we recommend choosing a plan with some extra allowance.
Which to choose: 20GB, 30GB, 50GB, or Unlimited?
Recommended for those who need 20GB
- Use Google Maps daily
- Primarily use LINE or email
- Also use hotel Wi-Fi
- Do not watch many videos
Even for 21 days, if you focus on maps and messaging, 20GB may be sufficient.
Recommended for those who need 30GB
- Use SNS daily
- Post photos and videos
- Frequently search for sightseeing information during the trip
- Have days without Wi-Fi
For a typical 3-week trip to Japan, 30GB is the most balanced capacity.
Recommended for those who need 50GB
- Watch YouTube daily
- Frequently view Instagram Reels or TikTok
- Use video calls
- Occasionally use tethering
For those who want to enjoy videos during the trip, the 50GB plan is recommended.
Recommended for those who need Unlimited
- Watch videos for long periods every day
- Use tethering for work
- Conduct online meetings
- Want to use data without worrying about limits
Even with an unlimited plan, there may be a Fair Usage Policy in place. Please check the usage conditions before purchasing.
How to save on data usage during a 21-day trip to Japan
Use hotel Wi-Fi
Using Wi-Fi at hotels for video streaming and photo backups can save on data usage.
Save Google Maps offline
Downloading maps before your trip can significantly reduce data usage.
Turn off auto-play for videos
Stopping auto-play for videos on Instagram, Facebook, and TikTok can help reduce data usage.
Check cloud sync for photos
For Google Photos and iCloud Photos, it is recommended to set them to sync only when connected to Wi-Fi.
Download videos over Wi-Fi
For videos you want to watch on planes or Shinkansen, make sure to download them in advance.
How to choose an eSIM for a 21-day trip to Japan
Check the number of usage days
If there is no plan for 21 days, you can also choose a 30-day plan.
Check the data capacity
For long trips, it is easy to run out of capacity, so we recommend having more than 20GB.
Check if it’s total capacity or daily capacity
Make sure to check whether it’s a total of 30GB or a type that allows 1GB per day before purchasing.
Check the start conditions
Some products start from the time of installation, so check the usage start conditions as well.
Check compatible devices
Before purchasing, please check the list of eSIM compatible devices .
Check the setup method
For first-time users, the eSIM setup guide can also be helpful.
Recommended eSIM for a 21-day trip to Japan
For a 3-week trip to Japan, if you primarily use Google Maps and LINE, 20GB is sufficient; if you use social media daily, 30GB is recommended; and if you also watch videos or use tethering, a plan with 50GB or unlimited is advisable.
For differences in pricing and usage days, please check Comparison of Japan eSIM Prices and Plans .
View Japan eSIM products and pricing plans
Frequently Asked Questions
Is 20GB enough for 21 days?
If you focus on Google Maps and LINE, it may be sufficient. For those who use SNS and videos daily, we recommend more than 30GB.
Is 30GB recommended for 21 days?
For a typical trip, 30GB is the most popular capacity. You can use photo posting and SNS with peace of mind.
Is 50GB necessary?
50GB is recommended for those who watch videos or use tethering.
There is no 21-day plan available
If there is no 21-day plan, choose a product that covers the usage days, such as a 30-day plan.
Can I set it up before arriving in Japan?
Many eSIMs can be installed before departure. The start conditions vary by product.
What if I run out of capacity midway?
Some products allow for additional purchases. If not, please purchase a new eSIM.
Should I turn on data roaming?
For many travel eSIMs, it is necessary to turn it on. Keep the main line off.
What if I cannot connect?
Please check the eSIM line, mobile data, data roaming, and APN in order.
For more details, please refer to How to troubleshoot when Japan eSIM is not connecting .
Conclusion
For a 21-day trip to Japan, it is important to choose a capacity that matches your travel style.
- Maps & LINE focused: 20GB
- SNS & photo posting: 30GB
- Video streaming: 50GB
- Work & Tethering: Unlimited
For long trips, we recommend choosing a plan with a little extra capacity to avoid running out.
You can check the eSIM for your trip to Japan at Japan eSIM products and pricing plans .
