Extended parking plans have been negotiated between the Royal Borough and the Olympic Delivery Authority (ODA) to encourage visitors to spend more time in the town.
Planning permission has been granted for two temporary parking sites to be set up in Braywick Park and off Stafferton Way, with specially-designated buses shuttling people to and from Dorney Lake.
These were initially set to open at 4.30am each day and close at differing times between 3-6pm.
The extension also applies to a park-and-ride site proposed for Windsor Great Park.
Each day of the Olympics at Dorney could attract up to 30,000 spectators.
Of those, 15,000 are expected to use the park and ride scheme, which will also operate at Upton Court Park in Slough.
The Maidenhead sites cater for more than 1,300 vehicles between them.
The Braywick site, which will be used during the Olympic Games only, will sit on existing parkland behind Braywick Heath Nurseries and Toby Carvery and contain 790 parking spaces.
Access will be provided via the current entrance in Braywick Road.
The Stafferton Way site will be based on vacant land previously used as a park-and-walk site in 2007.
Containing 615 spaces, it will be used during both Games.
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