Following the termination of 3G service on March 31st, 2026, VoLTE (Voice over LTE) must be enabled to make voice calls on the 4G/LTE network.

Note: Most modern smartphones already support VoLTE, and on many devices it is enabled automatically (so a VoLTE setting may not appear). If you don’t see a VoLTE option, make sure your Preferred network type / Network mode includes 4G/LTE or 5G.

iPhone

Note: From iPhone 12 onwards, VoLTE is typically available by default in supported areas, and you usually do not need to change any settings.

・Go to Settings → Cellular (Mobile Data) → Cellular Data Options → Voice & Data

・Enable VoLTE (if shown)

Android

(Menu names vary by device.)

・Go to Settings → Network & Internet / Connections → Mobile network

・Check Preferred network type / Network mode and make sure 4G/LTE or 5G is selected/available

・If you see VoLTE / 4G Calling / VoLTE calls / Enhanced 4G LTE Mode, turn it ON

If you can’t find the VoLTE setting

Some devices do not display a VoLTE setting because it may be enabled automatically or hidden depending on the model/region. If you cannot find the VoLTE option and are unsure, please contact the device manufacturer or Sakura Mobile Support.