IPhone 3G and 3GS handsets will be available to Orange customers from 10 November, marking the end of a two- year exclusive deal with operator O2.
Orange said it would offer the handset to pay as you go, pay monthly and business customers.
Customers taking out 24 month contracts worth £30 or £45 a month will get the 8GB standard handset for free.
The Orange tariffs are very similar to O2. The cheapest 24 month contract is £29.36, compared with £34.26 with O2.
"Since we announced the iPhone on Orange we have already seen more than a quarter of a million customers register their interest on our website," said Tom Alexander, head of Orange UK.
In September, both Orange and Vodafone announced that they would be offering the iPhone. Vodafone said the phone would be available on its network from 2010 but has yet to confirm pricing details.
O2 has offered the iPhone since its UK launch in 2007. By February 2009 over a million handsets had been sold.