Customers in the U.S. were privvy to the phones starting at 8 a.m. in each time zone.
A million people on Monday pre-ordered the phone in one day, breaking a record.
Some die-hard iPhone fans camped out overnight or even days for the phone.
"You don't even know how much I'm excited. After 34 hours of waiting, it's well worth the wait," said East L.A. resident Francisco Naranjo, who was first in line to enter the Apple store in Pasadena when the store opened Friday morning.
Orange County resident Miriam Ayad said she has the older iPhone 3GS.
"It's time for a new phone. It's kind of like glitching out on me, and I'm ready for something different. I'm excited. I'm sipping the Apple juice," said Ayad.
Martin Gijzemijter flew all the way from the Netherlands to pick up the 4S. He said he came straight to the Pasadena Apple store fresh off an 11-hour flight to get his hands on the new phone.
Despite the buzz surrounding the 4S, Apple critics say the new version isn't the overhaul they were hoping for. However, the phone's software-based personal assistant feature, called Siri, and the improved 8 mega-pixel camera seem to be enough of an upgrade for fans.
"It's really cool. The accuracy of the speech, it's amazing, actually," said Monrovia resident Brett Mirley.
There are also those with sentimental reasons for buying the iPhone 4S, just days after the passing of Apple co-founder Steve Jobs.
Ayad said she will be buying the white version of the phone due to the iconic iPhone image. She said Jobs is an inspiration to everyone.
Friday was also a big day for Spring customers, because they too can get their hands on an iPhone for the first time.
There was so much excitement over the new 4S that even Apple's cofounder, Steve Wozniak, waited in line to get one.
Wozniak rode his Segway to an Apple store in Northern California and was one of the first people in line.
He camped out just like everybody else, hoping to get his hands on his company's latest smartphone.
Wozniak said it's a different feeling when you wait in line to get something you're excited about.