Japan Unlimited eSIM: How Day Passes Work and When to Skip Them
An "unlimited" Japan eSIM almost always means a daily high-speed allowance, then slower data until it resets the next day. GoSIM's Japan day passes run on 5G and start at CHF 1.99 for 500 MB a day. If you want one eSIM for a whole trip, a 10 GB / 30 days plan for CHF 7.99 or 20 GB for CHF 13.99 is usually cheaper and simpler.
Oct. 5, 2026
What "unlimited" means on a Japan eSIM
Most unlimited Japan plans work this way: you get full speed up to a daily amount, then the speed drops for the rest of the day. At 1 Mbps, maps, messaging and music still work fine. At 384 Kbps, maps and WhatsApp work, but video and big uploads are slow.
GoSIM Japan day passes
| Full-speed data per day | After the daily allowance | Price |
|---|---|---|
| 500 MB | 384 Kbps | CHF 1.99 |
| 1 GB | 1 Mbps | CHF 2.99 |
| 2 GB | 1 Mbps | CHF 3.99 |
| 3 GB | 512 Kbps | CHF 4.99 |
| 5 GB | 384 Kbps | CHF 6.99 |
| 10 GB | 384 Kbps | CHF 8.99 |
Day passes are good for a stopover, a single heavy day, or topping up when your main plan runs low.
Day pass or total-data plan?
Most people use 1 to 1.5 GB a day in Japan: maps, trains, translation, Instagram and some video calls. For a 7-day trip that's around 10 GB, which costs CHF 7.99 on GoSIM's 30-day plan. For two weeks, 20 GB for CHF 13.99 is plenty. Pick a day pass if you only need data for a day or two, or if you'll stream a lot and want a fresh allowance every day.
| Trip | Good fit | Price |
|---|---|---|
| Layover or 1 day | 1 GB day pass | CHF 2.99 |
| 1 week | 10 GB / 30 days | CHF 7.99 |
| 2 weeks | 20 GB / 30 days | CHF 13.99 |
| Heavy streaming | 50 GB / 30 days | CHF 27.99 |
Networks and setup
GoSIM Japan plans connect to NTT docomo, KDDI/au, SoftBank and Rakuten Mobile, with 5G where available. Install the eSIM at home over Wi-Fi, turn on data roaming for the new line, and switch mobile data to it when you land. If you run low, you can top up the same eSIM instead of installing a new one.
Frequently Asked Questions
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