Cell phone companies will charge you an arm and a leg for roaming if you happen to venture overseas and use your phone without telling them. Avoiding these charges is easy.
If you don’t need to use your phone and want to rely on Wi-Fi, that’s very easy to do. Just download everything you need for your trip before you leave (don’t forget the maps) then turn off the cellular data on your phone (or just turn on airplane mode). This’ll prevent your cell phone company from charging you roaming fees on incoming calls or texts, and you’ll still have access to the data you need. There’s no need to call your phone company this way, it’ll just look like your phone is powered off to them.
If you’d prefer to still have access to your phone throughout your trip, we suggest going with a pay-as-you-go SIM card instead of signing up for your carrier’s international plan. When you arrive in a new country, buy a pay-as-you-go SIM, put it in your phone, and you don’t have to worry about additional fees because when you run out of minutes or data, the card will just stop working. The only caveat is that you unlock your phone ahead of time (and this only works with GSM carriers like AT&T and T-Mobile, but check with your carrier to be sure, some Sprint and Verizon phones may work as well).
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Based on Independent Traveler article.
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