Why does T-Mobile USA have so many iPhone users?

Lynnette Luna
T-Mobile USA made a surprising revelation by declaring it supports 1 million iPhone users on its mobile network, AllThingsD reported. What's more astonishing is the fact that iPhone users on T-Mobile's network don't have access to the operator's HSPA network; they have to use T-Mobile's slower EDGE network since the phone only supports AT&T's Mobility's (NYSE:T) HSPA bands.

Moreover, current iPhone users must get their phones unlocked from AT&T and actually cut a SIM card to get it to work over T-Mobile's network because the iPhone uses a smaller SIM card that T-Mobile doesn't carry.

With 10 million smartphones running on T-Mobile's network, that means iPhones account for 10 percent of all smartphones accessing the network.

What does that tell us? Either these folks really hate AT&T or they prefer cheaper service instead of faster data speeds. T-Mobile said the development reveals how aggressive the operator's rate plans are.

"Consumers appreciate having the flexibility to find the network service and rate plans that best meet their needs, so T-Mobile continues to be a very attractive option for unlocked phones," T-Mobile Communications Director Hernan Daguerre said in a statement to AllThingsD.

There may also be another reason why T-Mobile has so many unlocked iPhone users: international roaming. That factor was highlighted when Apple (NASDAQ: AAPL) announced earlier this month that it would begin selling unlocked GSM iPhones in the United States. "Buying an unlocked iPhone 4 allows you to choose your own GSM carrier, change carriers at any time, and even use multiple carriers if you travel frequently," Apple said on its website. Rather than paying roaming fees, those users with unlocked iPhones can purchase a pre-paid micro-SIM card from a local carrier while traveling.

Frequent travelers could already represent the bulk of unlocked iPhone users so far, given the fact that roaming charges--especially data roaming charges--can add up to thousands of dollars.

The unlocked iPhone will be interesting to watch in terms of gauging price sensitivity on mobile broadband. --Lynnette