If you are a SIMBA Telecom subscriber and intend to data roam in Japan. This is something that you need to take note.
To roam successfully, you must ensure that you are have a VoLTE compatible phone. This is a requirement of KDDI and Rakuten to data roam. With VoLTE Roaming, you can make calls to/from Singapore numbers for free (or 300 minutes to landline).
Secondly, you need a phone which supports most of the LTE bands commonly used in Japan KDDI and Rakuten. You can refer to this link for more information.
Update on 18/9/2023 : You can now data and volte roam on LTE band 3 of Rakuten networks.
Of course, you would also need to adhere to the basic requirements of setting the correct APN etc.
