The iPhone giveth AT&T, and the iPhone taketh away

AT&T’s iPhone sales declined in the third quarter, but that should come as no surprise following Apple’s earnings earlier this week.

AT&T benefited greatly, and exclusively, from the new iPhones previously released by Apple in the third quarters of 2009 and 2010. That didn’t happen this year, and AT&T’s year-over-year wireless revenue growth slowed as a result. The company reported $3.6 billion in profit, declining more than 70% from the year-ago period. Revenues were down 0.3% to $31.5 billion.

That said, AT&T is off to a running start with the recently launched iPhone 4S. The carrier had activated more than 1 million iPhone 4S’ through Tuesday, Ralph de la Vega, president and CEO of AT&T Mobility and Consumer Markets, said during the earnings call.

AT&T added 2.1 million total wireless subscribers during the quarter, surpassing the 100 million mark and ending the quarter with 100.7 million customers.

Once again, connected devices drove the lion’s share of net adds, accounting for nearly half of all new activations. Connected devices racked up 1,038,000 activations, resellers added 473,000, postpaid delivered 319,000 and prepaid boosted the bottom line with 293,000 activations.

iPhones accounted for more than half of the 4.8 million smartphones sold during the quarter while Android sales more than doubled year-over-year. Overall, smartphones represented nearly two-thirds of postpaid device sales.

The carrier ended the 11th consecutive quarter with a year-over-year increase in postpaid subscriber ARPU, which inched up 1.4% to $63.69.