Japan is phasing out 3G by 2026. Openline via DoCoMo/SoftBank/KDDI works on LTE and 5G; make sure your device supports Japanese LTE bands (Band 1, 3, 8, 18, 19, 26).

Practical check

Before travelling, verify your device advertises VoLTE support for the destination's bands. Google "Does [your phone model] support VoLTE in Japan?" or check the manufacturer's spec sheet.

If your device doesn't support the local VoLTE profile:

  • Data (Openline) still works normally.
  • Voice apps (WhatsApp, Signal, FaceTime, Zoom) work fine because they ride the data path.
  • Traditional voice calls to a phone number may fail — but Openline doesn't provide those anyway, so this matters only for your home carrier's line while roaming.

Still stuck?

Reach Openline support 24/7 through any of these channels:

When you write in, include your purchase code (the OL-… code we emailed you) and, if the eSIM is already installed, its ICCID (Settings → Cellular → tap the Openline line). That's enough for us to find your plan and diagnose without back-and-forth.