Ireland's Tanya Watson missed out on a place in the 10m platform final after finishing 15th in Wednesday's semi-final.
With the top 12 qualifying for the final stage, the 19-year-old's total of 278.15 was not enough to progress.
Watson, the first female Irish diver to qualify for the Olympics, made a strong start in her bid to advance from the semi-finals.
Her first dive earned her a score of 64.00 which placed her ninth, before she followed that up with a 63.00 that moved her up to seventh.
But Watson's fortunes changed drastically with her third effort as she posted her lowest score of the morning with a 39.15 that dropped her down to 15th overall.
A pair of 56.00s on her final two dives saw her regain momentum but she was unable to break back into the top 12.
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"The experience was amazing," Watson said of realising her Olympic dream.
"I was just so overjoyed to be here, and with coronavirus and all those worries, just reflecting on it, it's amazing that I got here and I competed, and I had a blast."
Analysing where it went wrong, the 19-year-old added: "My third one, I just kicked a bit late.
"My start was confident – I was really happy with other parts of the dive. Unfortunately, my entry wasn't so good.
"And then I pulled myself back up. I did a good fourth dive, really happy with that, especially as my fourth dive in training has really been not very good. For it to be one of my most consistent dives in competition, I was really stressed about that dive, and I'm really grateful that I managed to pull it off when I needed to.
"My last dive could have been a bit better, but after the dive, I was just so happy that I was an Olympian!"
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