Artistic director Danny Boyle confirmed the theme at a press briefing together with his creative director Stephen Daldry, BBC News reports.
Boyle said: "We'll be celebrating the whole of the country... there are so many 'Isles of Wonder'."
He added that the ceremony will be about the recovery of a land poisoned by an industrial legacy.
The largest ringing bell in Europe will be made for the ceremony and will be hung at the end of the Olympic stadium.
It is inscribed with a quote from Shakespeare's The Tempest, reading: "Be not afeard, the isle is full of noises."
Among other elements, the opening ceremony will feature NHS nurses. Boyle said that they are one of the things "unique about us... along with our sense of humour".
The 50-minute pre-show starts July 27 at 8.12pm (20.12) BST and the ceremony kicks off properly at 9pm with the ringing of the bell.
As previously announced, dance music duo and frequent Boyle collaborators Underworld will be the musical directors for the opening ceremony.
Artists reportedly approached for the event include X Factor winners Little Mix and Ashley Banjo from Britain's Got Talent winners Diversity.