Apple's latest smartphone was unveiled by Steve Jobs at the company's Worldwide Developers Conference (WWDC).
The new handset, which features an all-new design, has "well over 100 new features" including an HD screen, video calling, a gyroscope, a new iMovie app and countless other upgrades.
All three networks said the iPhone 4 will be available from June 24. However, no pricing details have been announced yet.
"We are very excited about the new iPhone 4 and are confident that our customers will enjoy a great experience on the Vodafone network," said Mark Bond from Vodafone UK.
O2 also revealed it will run an upgrade offer for a limited period that will allow customers still in contract to get their hands on a new iPhone. The network said it would release further details in the coming days.
"With three years' experience in selling the iPhone we are well placed to support the new device with the best overall experience, including making it easy for new and existing customers to get their hands one," said Ronan Dunne, UK chief executive of O2.
O2 has also created a dedicated web page where it will post further information about the iPhone 4 as it is made available.