Held at Mudgee, Will be looking to carry on his good form, where he finished in third place on Sunday at Bathurst, behind eventual winner and runner-up Nick North and Josh Stapley respectively.

Fifteen-year-old Kelly, who started triathlon when he was in Year 3, said he's dramatically improved his performances in the past few years, progressing from the short course to making his debut in the long course on Sunday gone.

"I thought third was pretty good for me [on Sunday]," he said.

"I didn't expect to be any where that on the field and I was very happy with my result.

"In the past couple of years [I've improved] enormously. That was my first race doing long course ever and before that, I did short course for about one and half years."

With the Mudgee triathlon expected to attract a host of experienced athletes from across the Central West region, Kelly is expecting a competitive race.

"Orange does has a lot of good athletes from up there," he said.

"I'm just going to try my hardest and have fun as well."

He said he's enjoyed the competitiveness between his father across the years, but Kelly believes his dad has "become a bit slow".

However, his father did say Kelly shouldn't get too carried away.

"I reckon we should have a hashtag no big head, to keep him grounded," James Kelly laughed.

"Being able to compete together with your kids in triathlon is something great, it's just unfortunate that he's so much faster than me.

"We just encourage him to have fun and do the best as you can and Will has done that right the way through. It's only in the past couple of years that he's improved heaps."

And while James Kelly finished well off his son in a time of one hour, 11 minutes and 40 seconds, he said he does triathlon for the enjoyment and to keep himself healthy.

"I'm never going to be at the pointy end," he said.

The 21^st edition of the Central West Inter-Club Triathlon Series will get underway in Mudgee on Sunday, with the main race starting at 9.25am.

The course will start with a two kilometre run, followed by a 250 metre swim, a 18.5 kilometre ride, a 250 metre win and a two kilometre run.