Cook walked the line at the Palo Alto store and took photos with customers before going inside to meet with safe and help welcome customers once the doors opened.
Cue made an appearance at the Stanford store and the new head of retail Angela Ahrendts was in Sydney for the launch.
"Phenomenal start to a historic day and an honor to be with our incredible team and first customers in Sydney," tweeted Ahrendts.
Take a look at a few of the photos below. You may also want to check out these videos of the huge lineups around the world.
Tim Cook just walked line at Apple Store in Palo Alto. Lots of selfies. Said he got new iPhone "several months ago" pic.twitter.com/XfkN2kZYmV— Martyn Williams (@martyn_williams) September 19, 2014
Phenomenal start to a historic day and an honor to be with our incredible team and first customers in Sydney. pic.twitter.com/28aww07wGj— Angela Ahrendts (@AngelaAhrendts) September 18, 2014