Finally with the update of iOS iPhone also supports eSIM.
So I tried it at once. Regarding eSIMThis Toyo economic articleIt is detailed.
First of all, at T-mobile of the US carrier which is also one of the easiest obtaining methods. Originally T-mobile has a prepaid account, but you can not move to eSIM and you need to take a new account.Special applicationESIM installation completed. This is easy.
However, it seems to be a problem in various places, but it is extremely difficult to establish an account after that. The setting is not completed in any way. Finally anotherT-mobile applicationI can set it with a text message of opening, but I can not log in again. Do not end, T - mobile. I could use it once in the field, but I can not use this account anymore. So we will repeat to prepare a prepaid eSIM account before going to America until a fundamental improvement is made. That is, no future.
So I visited AT&T. This also has a prepaid account. Unlike T-mobile, AT&T can directly transfer the prepaid sim number to eSIM. It takes time to visit the store and have the staff do the procedure, but it is safe and secure. Read the QR of the card you received and complete eSIM installation on the spot.
By the way, it is convenient that data communication is done by eSIM, and the telephone is number of Japan (because there is a possibility of coming from Japan), but if it is au it can not do it.Suzuki SmoothSays that au 's VoLTE specifications are due to it. There is no merit of eSIM with this. It is the same as disconnecting and inserting the shim to disable Japanese numbers. au, I am disappointed.
So, in the future, it seems that it will be used to tether with AT&T put in the iPhone XS max of the sub machine and not roam while keeping the main iPhone XS as au.
Or, depending on the number of days of stay, it is better to spend 980 yen a day on the first day free au world data flat rate. This is enough for 3 nights in Taiwan. Either way it will not be necessary to carry around mobile Wi - Fi routers for overseas. I started using prepaid SIM for overseas career because I do not want that, but it is released at the end of it.
eSIM or roaming? I finally got no need for extra things.