T-Mobile released its first quarterly numbers since adding the iPhone 5 to its portfolio and sales of the device are impressive. For the first quarter of 2013, T-Mobile said it sold 500,000 iPhone 5s to “new and existing customers,” quite a feat considering the U.S.’s fourth-largest carrier just rolled out the device to customers on April 12.

With all those new LTE-enabled iPhone 5s jumping onto T-Mobile’s network, the carrier reported it was still on track to have 200 million LTE POPs covered by the end of 2013.

Credit it to the iPhone’s attractive pricing, T-Mobile’s new “Simple Choice” plans or something else, but T-Mobile also managed to add a substantial amount of customers during the quarter. The carrier brought in 579,000 net customers during the first quarter, which it attributed to improving its postpaid net customer losses by 61 percent annually due to improved branded postpaid churn.

Not all the numbers were encouraging though as total revenues fell 7.1 percent annually. T-Mobile chalked this up partially to an uptick in branded postpaid customers who were adopting the company’s “Simple Choice” and value plans, which lead to a 9.9 percent annual decrease in service revenue. Customers moving to those plans also resulted in a 6.3 percent annual decrease in branded postpaid ARPU. 

All things considered, T-Mobile CEO John Legere sounded upbeat.

“Things only get more exciting from here, having brought T-Mobile USA and MetroPCS together to create the wireless industry’s value leader and premier challenger,” said Legere in a statement.

T-Mobile just finalized its merger with MetroPCS and the new combined company will now operate under the T-Mobile US, Inc. moniker.—and trade under TMUS.

T-Mobile US Inc.’s stock is up more than two percent as of 8:52 a.m. CT.