Actual sales figures were not announced, but AT&T did say that customers ordered more iPhones from AT&T than any previous model on both its first day of preorders, and over the full weekend.
The carrier also touted its strengths over competitors, noting that AT&T's network allows customers to talk and surf the Web at the same time.
Apple announced on Friday that officials at the company had been "completely blown away" by demand for the iPhone 5 on its first day of preorder availability. The company sold out of its batch of launch-day orders in just over an hour early Friday morning.
New iPhone 5 preorders are now advertised to ship within two to three weeks for all models.
Last year, the iPhone 4S set a new sales record for Apple, with one million preorders placed for the device on the first day. Total sales exceeded 4 million in the handset's launch weekend. It remained the top-selling smartphone in the U.S. until this August.
The iPhone 5 is expected to handily beat last year's sales records, as it is launching in more countries on its first day of availability, and at a faster rate around the world. At least one analyst believes sales could go as high as 10 million in the September quarter, which concludes at the end of this month.