But event director Rob Battochio said the 15th edition of the popular event is mainly for the "everyday competitor".

To mark the milestone year, organisers are championing the theme of fund-raising for charity partner Anglicare in 2014.

About 2000 competitors are expected to take part in the run-swim event at Belmore Basin on January 26.

"Australia Day is an iconic day to celebrate, and what better way to set yourself a fitness challenge?" Battochio said.

"We're trying to show the community fitness that can be fun, and anybody can do something like this."

A range of events are on offer, including the top-tier long course (900-metre swim and seven-kilometre run), the short course (400-metre swim and three-kilometre run) and an "Aquafun" event for children under 12 (a two-kilometre run).

This year the event will also include a 3.5-kilometre charity walk. Entry fees will go to Anglicare programs.

International triathletes Gwen Jorgensen and Aaron Royle will lead the red-hot field.

Royle booked a place at the Glasgow Commonwealth Games with his performance at the ITU World Championships in London in October and has since won the Noosa and Nepean (Penrith) triathlons.

He'll face some friendly competition from training teammates Ryan Bailie and Olympian Brendan Sexton.

Defending women's champ Jorgensen will set the pace in her division, but will be pushed hard by recently crowned ITU under-23s World Champion Charlotte McShane and teammates Grace Musgrove, Natalie Van Coevorden and Tamsyn Moana-Veale.

All are members of the Wollongong Wizards, a NSWIS high-performance unit that trains locally under Jamie Turner.

Entries are open online until January 23, or in person on the day.

Visit aquathon.com.au for more details.