It was a disappointing night for Team Ireland in the pool as both Patrick Flanagan and Barry McClements failed to progress from their heats.
Longford's Flanagan became the last Irish swimmer to make a first appearance in the water as he competed in the S6 400m freestyle event.
He finished 7th in a PB time of 5:40:48.
"My mum is probably like going crazy right now," he said. "I'm just so happy to be here and they were so good to me."
McClements meanwhile was competing in his favoured S9 100m butterfly.
Despite finishing strongly he came home in fourth place, agonisingly close to the top-three finish he needed. His time of 1:02.83 was just over a tenth of a second off Croatia's Kristijan Vincetic ahead of him.
It was his final event at a Games which had seen him achieve two PBs and reach a final in the S9 100m backstroke.
"I always knew I would final here and I did final," said McClements.
"I can't beat myself up too much but, looking forward to Paris, and yeah I have full confidence in myself that I will be on the podium there."
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