Sutherland Shire Council will do everything possible to keep beaches open to "stop people going stir crazy" during the coronavirus shutdown.
The council put extra lifeguards on duty on Sunday to ensure numbers at any location did not exceed 500.
The biggest gathering was about 300 people about 3.30pm before a southerly change kicked in.
Cronulla beach and the adjoining park were relatively quiet, with fewer beach-goers than some of the other beaches.
Mayor Carmelo Pesce said lifeguards patrolled the beaches and encouraged people to move along the Esplanade, where there were considerable numbers.
Cr Pesce said, after talking with surf club presidents, the council would do everything possible to control numbers and keep the beaches open.
"People will go stir crazy if they can't go for a walk on the beach or have a surf with everything that's happening," he said.
Cronulla beaches will be closed today if numbers exceed 500.
Sutherland Shire Council has put extra lifeguards on duty to patrol the beaches, monitor the situation and move people along on the Esplanade.
Large numbers were expected because of beautiful beach weather and the closure of beaches in the Waverley and Randwick council areas, including Bondi, due to fears of coronavirus spreading.
Mayor Carmelo Pesce, who is receiving reports every half hour, said at 10 am, Elouera beach had about 200 people, Wanda 110, North Cronulla 80 and Greenhills 50.
"If the number goes over 500 at a beach, we will close it down," Cr Pesce said.
Cr Pesce said his understanding was that the 500 limit at Cronulla beach would include the adjoining park.
Cr Pesce said hundreds of people were walking the Esplanade, but as long as they kept moving they would not be a problem.
Lifeguards had already asked a large group to move on, and the request has been accepted well, he said.
"We are getting the message out to people through the lifeguards and social media," he said.
"It's really commonsense - if you go to a beach or Cronulla Park and see there are already a lot of people there, turn around and go back."