Can I leave my primary SIM (the SIM I normally use in Japan) turned on?
Yes. You can leave your primary SIM turned on, but there are a few things to keep in mind.
If you do not plan to use your primary SIM, we recommend turning it off.
If you leave your primary SIM turned on
If you leave your primary SIM turned on, make sure that Data Roaming is turned off for that SIM.
If Data Roaming is enabled, you may incur high international roaming charges depending on your mobile carrier and plan.
In rare cases, your primary SIM and eSIM may interfere with each other, making it difficult to connect to the internet using the eSIM.
If this happens, turning off your primary SIM may resolve the issue.
If you do not plan to use your primary SIM
If you do not plan to use your primary SIM for calls or SMS, we recommend turning it off in advance.
This can help prevent unintended data usage or charges and may also provide a more stable connection when using your eSIM.
When turning off your primary SIM, be careful not to accidentally delete it.
Do not select options such as "Delete eSIM" or "Remove SIM."
If you accidentally delete your primary SIM, you may need to contact your mobile carrier and complete additional procedures to restore it.