Travelers to Southeast Asia, take heart: under a few circumstances, you don’t have to leave home without your phone. Cellphone roaming in Southeast Asia isn't just possible, it's very easy to do! Certain U.S. cellular phones will work in Southeast Asia, so if your phone meets a few conditions, you’ll be able to call home on your own handset to tell the folks how your trip is going.
The region’s major cities and tourist spots are mostly covered by each country’s cellular providers. Southeast Asia’s mobile penetration rate tops off in Singapore at 93%, Malaysia at 67%, and Thailand at 45%. The closer you are to the cities, the greater your chances of getting a signal. (A PDF map of GSM cellular coverage in the Asia-Pacific is available for download here.)
There is a catch – several of them, in fact. You’ll be able to use your phone only if:
- Your phone uses the GSM cellular standard;
- Your phone can access the 900/1800 band; and
- Your phone’s SIM can access the local networks – which means that
- Your provider allows international roaming; or
- Your phone is SIM-unlocked, allowing you to use prepaid SIM cards
Condition 1: Using the GSM Standard
Not all cellphone providers are created equal: in the U.S., digital cellular networks are split between GSM and CDMA. (Consult this About.com page for more information about the difference between the two standards.)
U.S. operators using the GSM standard include AT&T (formerly Cingular) and T-Mobile. Verizon Wireless and Sprint use the incompatible CDMA network. CDMA-compatible phones won’t be much use in a GSM-compatible country.
Condition 2: Accessing the 900/1800 band
Outside the U.S., Japan, and Korea, the world’s cellular phones use GSM technology. However, the U.S.’s GSM networks use different frequencies than the rest of the world: In the United States and Canada, GSM cellphones use the 850/1900 band – providers everywhere else use the 900/1800 band.
That means a dual-band GSM phone that works perfectly in Sacramento will be a brick in Singapore. If you have a quad-band phone, that’s another story: quad-band GSM phones work equally well on 850/1900 and 900/1800 bands. European phones use the same GSM bands as those in Southeast Asia, so no problem there, either.
Once you have both issues settled, let's move on to your choices: using your current plan to roam internationally, or buying a prepaid SIM at your destination. The pros and cons for each option will be laid out in the next page.
