DONNING the green and gold overseas for the first time, Queenslander Mollie O'Callaghan has set four new personal best times at the 2019 World Junior Swimming Championships in Budapest.
Swimming against top athletes from 155 different countries, O'Callaghan placed fourth in 100m backstroke, 100m freestyle and 50m backstroke, and helped her team to a silver medal in the freestyle relay.
She also set new personal best times in all her individual events.
"I was hoping to get into the finals and to achieve a personal best (so) I'm really happy," she said. "I've been training really hard lately."
In the lead-up to the competition, O'Callaghan trained nine times a week, including cycling, gym and core workouts.
She also attended a staging camp in Slovakia for a week immediately before heading to Budapest.
Her selection in the competition came after she hauled four gold relay medals and four individual medals at the national age championships in April.
O'Callaghan - a St Peters Lutheran College student - started swimming at age four and was competing at seven.
Coach Dean Boxall told the Jimboomba Times upon her selection to the world junior championships that O'Callaghan's strengths were her fight and tenacity.
"She has this ability to stand up and race at a very high level. She is an incredibly dedicated athlete who enjoys her swimming and training," he said.
In the coming months, she has her sights set on trials for the Olympics and the 2020 Junior Pan Pacific Swimming Championships.