I just got back from two weeks in Rome and Sorrento Italy and wanted to detail my travel experience with T-Mobile Simple Choices Plan and my Galaxy S4. In general, the phone experience was fantastic. Texting worked well. We made several phone calls. The 3G data speeds were fine. Having working smart phones was a huge benefit on the trip especially using Google Maps with GPS navigation and Google Translate. There were some issues which I will explain below but they were minor in my mind given that the service is free and worked so well in general.
You need to change two settings on your phone to make foreign travel work.
First, you need to enable Data Roaming. On my S4 running Android 4.4.4, go to Settings -> Connections -> More networks -> Mobile networks -> Data Roaming. When you enable Roaming, you get a pop-up that warns you that you may incur charges. Ignore the pop-up. Enable Roaming. I called up the T-Mobile help desk twice to be sure that I got the same answer both times. They told me that on the Simple Choice plan that you will never incur roaming charges. Even in the United States you should leave roaming enabled.
Second, in the Text Messaging app settings, you should enable Roaming Auto Retrieve.
When we landed in Rome, we got a text that said welcome to Italy and it explained that we had unlimited Texting and data. I had a phone cellular connection immediately but no data connection until I restarted the phone. Once it restarted, it got a 3G data connection.
The cellular connection was generally pretty solid. I found that the data connection would often disappear as I walked around. I don't know why. But it would generally recover the data connection if I restarted the phone.
Losing the data connection regularly was a bit of a hassle because it impacted Google Translate and Google Maps until I took some steps mentioned below.
We had great wifi connectivity in our Rome hotel and even used wifi calling to call back to the states for free. It was just like being home.
Calling and Texting
There were 5 of us traveling with various smart phones. We texted or called the normal US phone numbers and everything just worked. No special dialing. Somehow the system finds the other phone with a US phone number even though it is physically in Italy. We called each other on our phones in the middle of ancient Pompeii!
We often did group texts, that is texting to several people at once. That worked well but occasionally when a group text came in, the phone got confused and did not post the text to the group thread. It would post it to a text thread from the individual sender instead. Whenever this happened, the text message would fail to download. At these times it was convenient that my wife and I both had a phone because if the message failed to download on one phone, it was available on the other phone. I don't think a message ever failed on both phones at once.
I don't know if that problem is unique to Italy or or Galaxy S4s or Android 4.4.4 or not since we don't do much group texting at home in the US.
I texted back and forth with my family back home. It worked like a champ.
Google Maps and GPS Navigation
Maps and GPS navigation is an incredible godsend especially in Italy. The 3G data speeds were fine. We could put our earplugs in and let it walk us back to our hotel telling us each turn to take. And maps can tell you how to walk, drive or take the Rome metro.
But since the 3G connection would occasionally be unavailable, it is valuable to save (cache ) some Google maps for offline use on the phone. When offline, navigation does not work but the map is available and if there is a GPS signal, you still get a blue dot that shows you where you are. It was great.
I used the maps and navigate feature several times a day. Italy seems to specialize in bad signage. ;-)
To save a map for offline use in Google Maps, display the map you want to save then in the menu select "Your Places" and then the "View all and Manage" option under the Saved Maps section.
It is also very handy to save specific locations like your hotel and tourist destinations in Maps. It makes it easy to see them since Maps puts stars on their location in the map. And saved locations are easy to select in the My Locations list.
Translate was another huge help. The only thing is that you want to download the Italian language so that it works offline when the data connection fails. To download a language, go to Translate's Settings menu and select "Manage offline languages."
I bought the Rick Steves Kindle travel book and had it on the phone. Very handy.
I also had his app on the phone. The app let's you download audio walking tours. I bought an audio y-splitter so that my wife and I could have both of our earbuds plugged into one phone from which we would play the audio tour. It worked very well.
Having functioning smart phones in Italy was a massive benefit. It eliminates so much confusion and stress to be able to use Google Maps and know exactly where you are and how to get where you want to be. Ditto Google Translate.
I waited to post this until I could check the phone bill. It is exactly as advertised. No charges other than 20 cent per minute phone calls (Italy to Italy).
I don't want to sound like a T-Mobile employee but what blows me away is that T-Mobile made it all work in Italy with free texting, free data, 20 cents a minute phone calls on cellular and free phone calls on wifi. I have mentioned some issues above but I don't want to make too much of them. I was tremendously pleased with the service. I would never bother with going down the path of getting the phone unlocked and buying a local sim card.