Dawson won gold in the mixed 4x100m medley relay in Tokyo while competing with a back injury.
That turned out to be a bulging disc which caused sciatica and in the period since she has “questioned whether I wanted to be in this sport any more”.
Her time of 59.81 in the heats was her first time under 60 seconds since 2021 and a 59.74 in the final secured her Olympic return.
“I am so unbelievably grateful for the people who have got me back to this point,” she said. “It has been a big test of my mental character. There have been a lot of times I could have chucked it in.”
Tai competed at the Rio Olympics in 2016 but missed Tokyo because of injury. Since then she has had her right leg amputated to improve her quality of life.
She is targeting five events at the Paralympics with Wednesday’s backstroke win her first event of these championships, back at the venue where she won six world titles in 2019.
“In the pool I am proud of myself but outside of the pool this is the first time in my life since my amputation that I have had my independence,” she said.
“It [her amputation] was a big decision to make and I am proud I went through with it. I am the happiest I have been outside of the pool.”
Poppy Maskill finished second and Olivia Newman-Baronius third and they, like fourth-placed Megan Neave and fifth-placed Georgia Sheffield, also made the Paralympic nomination time in the S14 category to put themselves in contention for the Games.