Global Cell Service

Using a prepaid cell phone while abroad

Cellular companies in the U.S. use a number of proprietary networks for their cell phone service, and that means that a cell phone made to work with Verizon's CDMA network will not work on a GSM network such as those supported by T-Mobile and AT&T. This could be important if you travel overseas and would like to take your cell phone with you, because most European, African and Asian cell phones work on GSM networks. Be aware that American GSM phones and foreign GSM phones work on different frequencies, so you will need a specific tri- or quad-band world phone with multiple frequencies in order to use it abroad.

When traveling abroad, you'll have to swap out your SIM card in order to make calls on your phone. In order to do so, you will have to ask your cell phone service carrier to unlock your phone, allowing your phone to send signals on a different frequency. Some carriers will let customers have unlock codes as soon as 90 days into a contract, but others do so only reluctantly. Websites like www.unlock123.com will unlock Nokia phones for about $5. TheTravelInsider.info will do the same thing for most Nokia phones along with many other GSM world phones like Samsung, Siemens, Motorola and LG. Prices range from $5 to $30. The 2006 Digital Millennium Copyright Act has made it legal for individuals to unlock cell phones for personal use.

The advantage of switching SIM cards is that a local SIM card gives you a local phone number, making in-country calls inexpensive (avoiding very high roaming fees). In addition, most countries don't charge you for incoming calls. CNet.com warns that voicemail messages can cost more than at home, though.

Most U.S. prepaid wireless carriers will also let you provide your own phone, as long as it's unlocked and supports their network. So if you already have a GSM phone, you could buy minutes from T-Mobile or Cingular. Carriers may charge an activation fee if you don't buy one of their phones, however.

Most prepaid wireless carriers will let you make calls overseas, but international calls cost more. Virgin Mobile, Boost Mobile and all of the major carriers support international calls, but rates are sometimes high. Your best bet is to check before you travel.