IT was a cold induction into winter for a field of more than 160 swimmers who hit the surf at Mudjimba this morning for the Island Charity Swim.

The number represents a record for the annual event that raises funds for Nambour and Currimundi Special Schools.

Event organiser Jason Crowther of Atlas Multisports said conditions would be cold but otherwise perfect for the 11km swim around Old Woman Island and across to Mooloolaba.

A flotilla of 67 boats would support the 37 individual swimmers and 28 teams of two, four and six taking part.

Overnight temperatures dipped to below 10 degrees and the ocean to its coolest of the year at sub 24 degrees.

Garrod Cobey, Grant Edwards, Jason Crowther and Casey Munro took part in the annual Mudjimba Island Charity Swim.
Garrod Cobey, Grant Edwards, Jason Crowther and Casey Munro took part in the annual Mudjimba Island Charity Swim. Patrick Woods

Grant Edwards, a multi sport athlete who returns to the event for the second year, is one of several looking forward to completing the open ocean course after bad weather restricted the 11km swim to circuits of the bay at Mooloolaba.

"It's going to be bloody cold on the beach but I'm more concerned for those in boats and paddling," he said.

"It should be warmer in the water, I hope."

Swimmers left the beach at Mudjimba from 7am in 30 second intervals. Those taking part in teams would change swimmers once they go around the island and start the long stretch to the Mooloolaba finish.

The Island Charity Swim has generated well over a $1m in support for the two schools helping with the purchase of buses, air conditioning, sensory touch playgrounds, lap tops to aid language and learning among other upgrades parents would have struggled to raise funds for while managing already difficult lives.

Rather than being a race, the swim offers participants the reward of challenging their fears in an open water environment.

So powerful is the experience that many return to the event every year, achieving benchmark entry fund raising targets of $1000 for individuals, $1500 for teams of two, $2000 for teams of four and $3000 for teams of six.

Swimmers would be up to two kilometres from the beach at different points of the course.

They'll be welcomed onto the beach opposite at the first Parkyn Parade roundabout by supporters and students and parents from the two schools from about 10am.

A five kilometre short course around the bay at Mooloolaba will be staged for the first time as part of this year's event.