The flags are up this weekend on Wollongong council's 17 patrolled beaches for the start of the swim season.
While beaches and rock pools are open, the council's supervised pools remain closed in line with the current Public Health Order.
The same COVID rules apply - wear masks when not exercising and keep up social distancing, a council spokesman said.
Also, people are encouraged to swim and go and not hang around at the beach.
"If your usual beach is a popular one, consider visiting one of council's other beaches if you're keen to swim," the spokesman said.
"We all need to continue doing the right thing until vaccinations increase and restrictions ease."
You should not enter the water if there are no red and yellow flags. Never swim alone and never drink alcohol and swim.
"Our lifeguards and lifesavers are always happy to give advice about beach conditions," the spokesman said. "Go and say hi, and get the latest updates from them before you go in the water."
Patrol hours are available on the council website.