iPhone with dial sims question

I have a thread going on the electronics page. I have asked the same question about using dual SIMs in Italy using a Verizon phone. Verizon told me that I cannot but others have said I can. I'm still researching and am interested in reading other responses to your question.

Buy a GoogleFi phone. Worked flawlessly last year in Sweden and Germany/Austria. Used it daily for Google map directions and loved it. No additional sim cards needed.

Thanks for suggesting the GoogleFi. I had not heard of it before. It seems like a lower cost answer to my problem if I use my iPhone. I like that I can set it up before I leave home.

I am still wondering how the dual sim works in a phone. Can I shut one sim off so I do not accidentally incur data charges outside of the country? I figure I can then enable it when I am using the hotel's WIFI and see my messages.

I have a dual SIM phone. Somewhere in the phone settings it allows you to select which SIM is the default for outgoing calls and data connections.
"Are there two sets of Cellular Data where I can turn it on or off for each app" - not for each App, for all App's

For incoming calls you can configure different ring tones for the two SIM's - if you want to.
If one of your SIM's charges you roaming charges for incoming calls you would still get hit by that. If you want to avoid that simply remove the SIM (than you don't need a dual SIM phone), but then you are unreachable on that number.

Can I shut one sim off so I do not accidentally incur data charges outside of the country? I figure I can then enable it when I am using the hotel's WIFI and see my messages.

Shutting down one SIM is the same as removing it, then you don't need a dual SIM phone.
If you are on WiFi you are not using either SIM, you are not using the cell phone network at all. You can use WiFi without any SIM's in your phone.

Chris,
Thanks for clearing up how the dual sims work. I couldn't find anything on my question so I appreciate you taking the time to post an answer. I also appreciate all the other responses because I now see I have more options for cell service in Europe.

I do what Chris does only I have mine set to ask which sim I want to use before making a call.

I also try to use Skype because it costs much less.

I went to Italy with my iPhone 10s in September. Verizon is my normal carrier. My regular cell number is set up on my eSIM with a second line being on the removable SIM. It took 5 minutes for the woman at the TIM store to pop out the SIM card and replace it with the Italian card. In “Settings” you go to “Cellular” and you will see 2 “cellular plans” with numbers shown for each. At the top of the page, you will see “cellular data.” Touch it and you can designate the foreign phone number as the data number.

Thank swbfey1. I suspected that the Verizon agent was wrong about using an Italian SIM card in Italy.

One more question - How did you transfer your Verizon data to the eSIM?

More info about dual SIM cards can be found in Apple support. Hope it isn’t TMI and causes confusion.

https://support.apple.com/en-us/HT209044

Thanks Rocket. The Apple link answered a lot of questions about the use of dual sims.

Again, I suggest Googlefi. No need to waste time getting or buying SIM cards. When in the foreign country, it picks up the network automatically. Will switch automatically between countries. It charges by gigs of data you use. For 14 days in Germany my husband and I (together) used 2.6 gigs of data at $10 per gig. No fooling around with SIM cards. We used the phone constantly for Google maps and travel info.

I have never heard of google Fi so I spent some time looking it up. Fascinating system and might be a cheap alternative to try on a European trip. There are not as many anti-Fi reviews as enthusiastically evangelical reviewers so a few hours on the Net could be enlightening. Of course, the webs are crowded with loud and angry voices, and, if you read between the lines, you may see many of the negative experiences are based on user errors and bollixed payment setups. Several of the high tech review sites are quick to point out the user base for google Fi tends to be tech-savvy and relies mostly on self-support forums. Customer support is often described as poor. Fi is a mobile virtual network operator (MVNO) that piggybacks on existing cellular networks in the States and 200 countries. Basically, Fi hops on and off whatever system is available wherever the phone is located.

One can apparently bring one's own phone but loading up google Fi on an iPhone appears to remain a beta product, requiring running an Android-based app on top of the iOS in addition to replacing the SIM. Easier, naturally, to just buy an Android phone (Pixel3 <$400, Pixel 4XL <$900, Moto G7 <$300, used Android phones are easily found).

Back of the envelope (and I am not a user with ANY experience), with two minimum phones and unlimited coverages for two would be roughly $1000 for two months, far less, naturally, if you don't need the hardware, about $250, less again if you don't need unlimited data, maybe $100-$150 fo pay-as-you-go. According to people who are supposed to know this stuff, Fi is not the least expensive option, not the easiest to set up and use, nor the best option for high data users. You gotta do the research.

Plenty of caveats and you must have an active account and data connections established and tested in the States long before connecting to the international services. If you travel internationally often, and have the cranial capacity to learn two phones, having a dedicated Android phone on google Fi might be a viable economic alternative. Just do't try to get it all together the afternoon before your plane leaves.

Do you have an Apple store in the neighborhood? Check the schedule for advanced iPhone instruction classes and then hang around to talk to the session leader, set up an appointment if necessary to discuss the eSIM system. I've looked hard and long at Apple's information and I'm pretty sure I'm still clueless.

We have had good luck with Googlefi. It is best that you purchase one of their phones to have the best service and least problems. Works for us.

I just had my iPhone SIM changed to an eSIM. Went into the ATT store (who is my provider) and they did it after consulting with other employees who knew how. My "everyday" line is now on the eSIM. I don't have a physical SIM card installed. It works just fine.
When you install a second physical SIM card, it will show up as a secondary line. you get to name them, Primary and secondary or whatever. You can choose which line you want to be active. So, to answer your question, there are two sets of cellular data. you can turn off your "everyday" phone data when you get to Germany and just use the data from your International SIM card.
Read up on it on Apple's website for more custom features using Dual SIMs.

Just make sure the iPhone you are buying has the Dual SIMs capability.