Questions about how the eSIM card works for Japan

Hi there, I have a question about the eSIM card: I bought an eSIM from Saily for my trip to Japan in 5 days. What should I do with my Samsung smartphone? What should I do with my current SIM card: deactivate/remove it? It says activation in Japan is automatic—what does that mean exactly?

Hi there,

First, your phone needs to be eSIM-compatible. If it is, it has a physical SIM card, which you leave in place, and an eSIM option that you activate by scanning a QR code sent by the seller. The card can be activated as soon as you're in an area covered by the eSIM, so for you, that’ll be upon arrival in Japan.

Michel

Hello,

First, your phone must be eSIM-compatible. If it is, it has a physical SIM card, which you leave in place, and an eSIM option, which you activate by scanning a QR code sent by the seller. The card can be activated as soon as you're in an area covered by the eSIM, so for you, that’ll be when you arrive in Japan.

Michel

Thanks so much. That’s gonna help!

Hey Michel, what happens if the network the eSIM connects to doesn’t work (dead zone) while it still works with your usual carrier?

Isn’t there a risk of switching to the other SIM card and racking up huge fees?

Wouldn’t it be better to temporarily block your plan or disable international roaming on it?

Once the eSIM is installed, the phone settings let you manage both SIMs independently (the French SIM or eSIM, and the Saily eSIM).

One initial option is to completely disable the French SIM during the trip and only use the Japanese one. In this case, there’s no risk of exceeding your plan, but you won’t be reachable on your usual number (neither by call nor SMS). So it’s best to avoid this if you want to receive urgent calls.

The best compromise is to keep both SIMs active at the same time but disable roaming on the French SIM.

On iPhone, there’s an option to choose which SIM consumes data and set a priority order. I’m not too familiar with Android, but it’s probably similar. Just be careful—if roaming isn’t disabled and you’re out of range of the Japanese eSIM, it might automatically switch to French data. So it’s better to disable roaming.

Thanks for the details.🙂