Roaming and eSIM side by side
| Home carrier roaming | Travel eSIM | |
|---|---|---|
| How you pay | A pass or add-on from your carrier | A prepaid plan, paid once |
| Your number | Calls and texts work as usual | Data only, your own SIM keeps the number |
| Set-up | Switch on data roaming, read the carrier's Japan rules | Install at home, switch on after landing |
| After the allowance | Depends on the plan: slower speed or extra charges | Listed in the plan: daily plans slow down or pause until the next day |
| Best for | A day or two, or when you must take calls | A week or more, or when you want a fixed cost |
Rules differ between carriers. Read your carrier's page for Japan.
Five checks before you decide
- What exactly is included? A pass, a data bundle or pay by use? Ask which one applies in Japan.
- What happens at the limit? Some plans slow down after an allowance, others bill extra.
- How is a day counted? Passes can count by calendar day or by 24 hours, so ask before a trip of several days.
- Which network will you be on? Roaming uses your carrier's partner networks. A travel eSIM lists the Japan networks live, further down this page.
- Do you need calls or codes? Bank codes and calls come to your number. With an eSIM your own SIM stays in the phone and still receives them.
Save your carrier's Japan terms as a screenshot before you fly. Then you can compare the daily charge, the speed cap and the end date with the eSIM plan, line by line.
Use both: keep your number, put the data on an eSIM
- Leave roaming off on your own line
Your home line then cannot use mobile data in Japan by accident. See data roaming on or off.
- Install the Japan eSIM at home
Use Wi‑Fi before you fly. The steps are in how to use an eSIM in Japan.
- Choose the eSIM for mobile data
Switch on data roaming for the eSIM line only. Calls and texts stay on your SIM: see iPhone Dual SIM.
More ways to avoid surprise bills: how to avoid roaming charges.
Japan networks and plan sizes
- Networks for JapanKDDI/au, NTT docomo, Rakuten Mobile and SoftBank
- SpeedUp to 5G on all four networks. Where there is no 5G, you connect over 4G/LTE.
- Internet runs viaSingaporeDepending on the plan. Banking or streaming apps may treat you as being there.
Not sure how much data you need? How much data you need has typical values per day and trip.
Prefer a daily allowance? 1 GB per day · 7 days for €9.49: full speed up to 1 GB a day, then 1 Mbps until the next day.
Picked like in our shop: the cheapest plan with about 0.7 GB a day. Live prices for Japan.
Questions and answers
Is roaming in Japan expensive?
It depends on your carrier and plan. Some include Japan in a pass, others charge by the day or by usage. Read your carrier's page for Japan before you fly.
Will I still get calls with an eSIM?
Yes, on your own SIM. The eSIM carries data only, so your number keeps working for calls and texts.
Do I switch roaming off when I use an eSIM?
Off on your own line, on for the eSIM line. See data roaming on or off.
Which is better for a short stopover in Japan?
For a day or two, roaming can be enough if your carrier has a pass you are happy with. For more days, a prepaid eSIM keeps the cost fixed.
Can I keep roaming as a backup?
You can, but leave data roaming off on your home line unless you need it, so nothing is charged by accident.
Updated 24 Oct 2026 · checked against our live catalogue
How we check our data · Prices and plans come live from our catalogue; facts come from official sources, listed where we use them.
