Sprint also revealed that the iPhone has played a major part in bringing new customers to the carrier, as 40 percent of iPhone sales in the June quarter were to new postpaid customers. In comparison, last quarter Sprint sold 1.5 million iPhones and 44 percent of those were to new customers.
While Sprint's iPhone sales held steady quarter to quarter, AT&T saw iPhone sales fell to 3.7 million, down from 5.5 million in the March quarter, while Verizon's 2.7 million iPhone sales in the June quarter was a decrease from the 3.2 million activated at the start of the year.
Sprint ended the most recent quarter with more than 56 million subscribers. The carrier is the third-largest in the U.S., behind Verizon and Sprint, and along with T-Mobile is considered one of the "big four" domestic wireless providers.
Sprint saw its wireless equipment net subsidy in the second quarter grow to $1.5 billion, up from $1.1 billion a year ago. That increase was attributed primarily to Apple's iPhone, which has a higher subsidy rate per handset compared to other smartphones.
iPhone subsidies also accounted for an increase in sales expenses year over year, contributing to an operating loss of $629 million. But the carrier's postpaid net additions of 442,000 represented an increase of 68 percent sequentially, thanks to continued strong iPhone sales.
Sprint reported a total net loss of $1.4 billion and a diluted net loss of 46 cents per share in the second quarter of 2012. That compares to a net loss of $847 million and diluted net loss of 28 cents per share in the second quarter of 2011.