The National Eisteddfod will halve the size of the camp site to be set up in Pontcanna Fields following a campaign by residents.
A 50-acre area of Pontcanna Fields was due to be closed off so up to 750 caravans could be parked there for the festival.
But now a maximum of only 338 caravans will be allowed on the site - which has been cut to below 25 acres.
The reduction comes after the Bute Parks Alliance raised concerns that the camp site could leave Pontcanna Fields in a flood-prone, muddy state - as it was left when the last time the Eisteddfod came to Cardiff in 2008.
Which areas of Pontcanna Fields will be closed off?
An Eisteddfod spokeswoman said: "An area between the riding school and the Blackweir path will be closed to the public from July 23 until August 18.
"There will be no buses on Lime Tree Avenue. However, a waste vehicle will need to drive to the Rugby Club occasionally.
"The camp site associated with Maes B (music festival) has been moved to Fitzalan.
"The path to Blackweir Bridge will remain open and no vehicles will need to drive along this path. The caravan site perimeter is to the north of the path.
"There will be 65 camping pitches on the site."
Public access to large areas of Pontcanna Fields and along Elm Tree pathway towards Blackweir Bridge will be maintained throughout the summer and existing cricket wickets will be protected as will the two rugby pitches, Cardiff council said.
A shuttle bus service will now run from Western Avenue – a change from the originally proposed location of the Bragdy a Chegin pub.
Alcohol will be sold on site alongside food for seven days from Saturday August 4 onwards. There will be no off sales allowed.
Bute Parks Alliance, in a Facebook post, said it has suggested alternative venues for camping sites for future events, including Alexandra Head, Hamadryad Park, Severn Oakes Park, Cardiff City Stadium car park.
'Eisteddfod organisers appreciate importance of parks and green spaces in Cardiff'
A spokeswoman for Cardiff council said: "Cardiff is excited about the return of Wales’ principal culture and language festival to the capital this summer and preparations are well under way.
“The Council has met with residents and stakeholder groups regularly ahead of the event regarding the camp site at Pontcanna Fields and has worked very closely with Eisteddfod organisers who appreciate the importance of the parks and green spaces to the people of Cardiff.
"We are grateful to all of those who fed back their thoughts and ideas and who have constructively helped us to shape the final event plan.
"The potential location of all events in Cardiff is considered on a case by case basis, depending on the event’s requirements and the suitability of available spaces in the city.”
