Using your phone in Outside of the US:
This page was written so long ago that it was all out of date. I was using a NexTel phone when I wrote it. Of course, NexTel was bought by Sprint which was bought by T-Mobile. So, now, it is all new and very simple.
4) The newer smart phones, just contact your carrier before you start your trip to set it up for overseas services. We did that and it worked great on our last trip to Cabo San Lucas as well as to Cancun. We also used it in Africa and Europe. Keep in mind that, depending on where you travel, you may pay about $1.50 to $2 per minute for calls that you make. We just traveled down under again and our data was unlimited and phone calls that we make were from 20 cents to a dollar per minute.
Another option is to purchase an overseas phone and just use it for your overseas travel. We did this several years ago for our first trip to Europe. We purchased them from Mobal Communications. Unfortunately they are no longer providing this service.
Many people choose to pick up a local sim, or these days use an e-sim to turn their phone into a local phone. We have not done anything in the past few years other than to just make sure that our international plan was in place.
You will want to install all of your travel apps on the smart phone so you will have those tools with you while you travel, but remember that some apps use data, such as navigation apps, and they will increase your data costs overseas. We always download the maps from Google maps so that they are on the phone and don’t need data.
Keep in mind that things change all the time.