Leading the charge into the water will be Algoa FM DJs, all of whom will be "blinged out and colourful for the occasion," says the station's programme manager Baydu Adams.
The dip will start promptly at 7.20am, but everyone can gather at the beach from as early as 6.30am.
Life guards will be on duty.
The Spring Day dip was started by Algoa FM in 2014, and the response was such that it was decided to make it an annual event, he says.
Beaches to head to on Spring Day are Nahoon in East London, Hobie in Port Elizabeth and Santos in Mossel Bay.
First to dip their toes in the water in East London will be Border Drive DJ Gordon Graham.
In Port Elizabeth it will be DMB presenter Charlton Tobias.
Jacques Arendt, presenter of the Garden Route drive-time show on weekday afternoons, will be leading the swimmers into the water in Mossel Bay.
"We invite as many people in the surrounds to bring your bling and colour, and join them for a bit of fun," says Adams.
In East London the fun will also be for a good cause.
Early morning swimmers at Nahoon will be asked to donate at least R5 to support the East London Child and Youth Care Centre, the largest children's home in the Buffalo City metro.
Staff have been working without pay and children have missed school due to delays in subsidies, according to the centre's social worker and fundraiser Larne Robus.
"We thought our annual Spring Dip will be a good opportunity to support the East London Child and Youth Care Centre and reach out to this organisation in need", says Algoa FM's PR and CSI Manager for Algoa FM, Jennilee Peremore.