Trickett, 25, announced her comeback late Wednesday and said she wanted to be eligible in time under international drug-testing protocols to represent her country again at next year's world championships in Shanghai.
The former 50m and 100m freestyle world record holder retired last December, citing a desire to move on to the next stage of her life.
But Trickett said she started to realise in recent months that she still felt the need to compete and she had already resumed light training with her coach Grant Stoelwinder.
"I think it really solidified it at Pan Pacs (Pan Pacific event in California last month) seeing the guys race," Trickett said on television.
