The girls travelled to Sydney Olympic Park Aquatic Centre to compete against the best swimmers in the state.

Although there were up to 30 athletes in each event, only the top 10 swimmers from the heats progressed through to the finals.

The top three swimmers from the finals qualified for NSW All Schools Swimming Trials.

Porscha performed in the multi-class category for swimmers with a disability, and therefore was not required to participate in heats as there are less swimmers in that category.

The duo's full results were as follows: Zahli placed third in her heat and progressed through to the finals, finishing in 9th place.

She came ninth in the 100m freestyle heat, but performed best in the 100m breaststroke where she came second in the heat and progressed through to the finals, finishing in fourth place by a fingertip.

The latter of those results was as impressive as it was devastating for the young star.

Porscha came second in the 50m freestyle and third in the 100m freestyle, 50m backstroke, 100m backstroke, 50m breaststroke 50m butterfly and 200m IM.

Zahli's mum, Belinda, said she was thrilled with her daughter's efforts and thought her performance in the 100m freestyle in particular surprised a few people.

"This year she made the 100m freestyle for the first time so she was pretty stoked with that," she said.

"Because when she goes to regionals at Newcastle they do have a very hard group to get through because of all those Newcastle and North Coast swimmers that come to that area.

"So she actually came through in third spot so it was actually a bit of a surprise to make it to Sydney for that one."

It was also Zahli's first time making the finals for the 100m breaststroke and 50m freestyle.

Both girls will move forward to NSW All Schools championships on May 28 in Sydney.