There are three ways you can get GSM phone service while traveling around the world. We don't discuss a fourth way – signing up for a regular monthly account in a foreign country – because this would commit you to a year or more of service and require you to meet local residency and credit checks, making it almost impossible to qualify for. Each of the three practical solutions has benefits, and most also have disadvantages.

Roaming with your US GSM Phone

This is obviously the easiest approach. If you already have GSM service with a US wireless company (most modern AT&T, Cingular and T-mobile phones are GSM) then you can probably ask your service provider to switch on the global roaming feature and simply use your present phone and phone number anywhere in the world they have roaming agreements.

But there are plenty of problems with this approach.

• Your US GSM phone might not work in many foreign countries – see article "Part Three: What sort of international cell phone do you need?".
• It will be expensive for you. You'll be paying anywhere from $1 to $6 per minute for every phone call you make or receive.
• Although it will be convenient for friends and associates back home to call you – they simply dial the number they already have – this means you'll be paying for all these non-essential calls, also at the same $1-6/minute rates.
• It will not be convenient for anyone in the countries you are visiting to call you. Even though you might be in the next hotel room, they will have to phone your US number to speak with you – making it an expensive international call for them as well as you.

Simply roaming with your US GSM phone is a viable solution if you only travel internationally very rarely and if you will be very careful only to use your phone for the very shortest of emergency calls, not for casual and normal calls. But what is the sense of having a phone with you but never using it?

Sadly, the high cost of international roaming charged by the US carriers makes the idea impractical for most of us, and not all of us already have GSM service and an internationally compatible phone, and so there are two other strategies to consider instead.

Using Pre-Paid SIM cards for each country you visit

This is the best solution for most people. A pre-paid SIM card for each country you visit gives you a local phone number and local calling rates for calls within that country.

It is easy, convenient, and relatively inexpensive for you to call other people in the country you're visiting, and easy and normal for them to call to you on your local number, too.

Most services even offer you free incoming calls, so you can receive calls from people anywhere in the world at no cost to you.

The cost of buying a SIM card is anywhere from about $30 - $60, and sometimes this includes some free call credits as well. You then simply pre-pay for extra call credits as you need them, often by a process as simple as just calling your credit card number in, over the phone, to the billing center for the phone service.

Usually SIM cards stay active for six months or more, so if you're visiting a country regularly, you don't need to buy a new SIM for each visit.

If you are visiting a lot of different countries during your journey, it can be confusing for other people to keep track of which country you're in and which number to call you at on any given day. This is where the next option can be more helpful.

Global Roaming GSM Service

A couple of phone companies (such as Telestial.com) have developed special SIMs and accounts that enable you to use their SIM in your phone in a large number of different countries, while paying relatively low rates for all calls in all the countries you visit.

The benefit for both you and people seeking to call you is you have a single number that everyone, everywhere, can use to contact you, no matter which country you're in (assuming you're in one of the approximately 90 countries that participate in these programs).

The compromise you need to make is that in return for a fixed number, you're going to be paying more to make and receive calls than you would with local SIMs. However, the rates with our Hop Global Roaming SIM are very much lower than you'd be paying with a US wireless provider – 95c a minute to make a call and only 35c a minute to receive a call.

How to Choose Which Option is Best for You

This table will help you select your best phone service strategy for your international travels.