Australia’s best swimmers are in Brisbane this week for the world titles selection trials.

The world championships will be held in South Korea next month, with just two spots up for grabs in each individual event.

Here are the big names who will be looking to stake their claim.

Kyle Chalmers

The “Big Tuna” is not only getting faster, he is getting more versatile.

Chalmers sounded an ominous warning at April’s national titles by winning his pet event 100m freestyle in a personal best 47.48 seconds – faster than when he claimed a shock Rio Olympic gold at the age of 18. But he is no one trick pony. He also racked up 200m freestyle and 100m butterfly gold.

Signs are good that Chalmers can throw down the gauntlet to American all-rounder Caeleb Dressel ahead of next month’s world titles with more selection trials gold.

Cate Campbell

The heartbreak of Rio must now seem an eternity away for Campbell.

The 27-year-old is now the benchmark for 100m freestyle after taking 12 months off and exorcising her 2016 Olympic demons by blowing away last year’s Pan Pacs field with a stunning five gold haul.

Favoured to not only hold a class 100m freestyle trials field also featuring her sister Bronte, Emma McKeon and Shayna Jack after winning April’s national title, Campbell is also tipped to reclaim the 100m crown at next month’s world titles for the first time since 2013.

Ariarne Titmus

The queen of Australian middle distance swimming, Titmus is ranked No.1 in the world in both 200m and 400m freestyle. And she is showing no signs of slowing down.

Middle distance Queen: Ariarne Titmus. Photo: Getty

Titmus fired a warning shot by setting a new 200m Commonwealth record at April’s national titles, cracking the magical two minute mark. It added to the swag of Commonwealth Games, Pan Pacs and world short course titles she claimed in 2018. And she is just 18.

The young gun may look a class above at the selection trials but will be out to send a warning to great US rival Katie Ledecky ahead of the world titles.

Emily Seebohm

After skipping April’s national championships, all eyes will be on Seebohm as she prepares to become the first woman to claim three straight world 200m backstroke titles in South Korea next month.

Instead of the Australian titles, Seebohm opted for international competition by contesting the inaugural $A5.5 million FINA Champions Swim Series.

Seebohm may already have the world titles in her sights but she won’t have it all her own at the trials in Brisbane with young guns Kaylee McKeown and Minna Atherton breathing down her neck.

However Seebohm is showing no signs of slowing down, even considering extending her already 12-year national team tenure until the 2022 Commonwealth Games.

Mack Horton

The Olympic 400m champion will be out to regain form ahead of the world titles at the trials.

Looking for form: Mack Horton. Photo: Getty

It remains to be seen if Horton will reignite his fierce rivalry with controversial Chinese champion Sun Yang at next month’s world titles.

He has brushed the 1500m, concentrating on 200m, 400m and 800 freestyle at the trials. He skipped April’s national titles where Kyle Chalmers dominated the 200m and Elijah Winnington lay down the gauntlet by claiming the 400m crown.

Jack McLoughlin also appears to have Horton’s measure over 400m and 800m after upstaging the Rio star at the 2018 Pan Pacs in Tokyo.

-AAP