What breaks when you travel on a data-only eSIM — checked country by country.
Japan · The default messaging app in Japan — restaurants, hotels and shops use it
Likely, with a number that can receive texts.
Reports agree that LINE accepts a foreign number rather than requiring a Japanese one, so a number that can receive texts — your home SIM, say — should work. The same reports say verification fails more often on numbers outside Asia. None of this is confirmed by LINE itself.
Several independent guides agree on the substance. LINE's own help centre text could not be retrieved for direct quotation.
How sure we are
This rests on consistent reports from travellers and guides, not on anything the company has published.
Next check
By 6 Nov 2026. Apps change their sign-up rules without notice; if you see something different, tell us at [email protected].
Won’t take a foreign number
Refuse lines without voice calls
Need a number that can receive a text
Work on a data-only eSIM on its own