After you've made sure your cell phone will actually work in the country you're traveling to, you'll want to make sure you're signed up for your cell phone company's international roaming plan for voice calls. All major service providers have them, and they're usually about $5 per month.
As long as the cell phone will work in the destination country the best solution for occasional travelers may be to simply sign up for their carrier's international calling plan and use an existing mobile phone for voice, texting, and data roaming.
These international voice plans usually save you about 20% or more on voice calls made from other countries. But make sure to check the rates, because even with that savings, the calls are usually pretty expensive. Typically they start out (even discounted) at about $1 per minute.
You also need to take the second step and consider how and when you'll use your phones data features. Data roaming can quickly rack up huge cell phone bills, especially if you haven't shut applications or background features that use your data plan.
Today's smartphones and iPhones can consume huge amounts of data, especially when running applications ranging from online maps to Internet radio. It might not be big deal at home, but using all those apps we've become accustomed to can really make the international data roaming fees add up. If you plan on using a lot of data services while traveling, make sure you check with the carrier to see if they offer international data roaming plans.
For example, AT&T offers data roaming plans that can make roaming much cheaper. If you're going to be traveling internationally and using your phone's data services, it's important to sign up for one of these plans in advance, otherwise, you can expect an extremely large roaming bill when you come home.
Signing up for International roaming plans and data plans aren't the only options. You may also want to consider purchasing a specialized international phone for traveling. These international cell phones often come with reduced data and international roaming rates.