Swim Ireland have announced their teams for the 2021 FINA World Championships (25m) in Abu Dhabi, United Arab Emirates and the LEN European Championships (25m) in Kazan, Russia.
In the main, athletes were selected to compete in one or other of the two events.
It is unusual for both to take place in the same calendar year.
The pandemic has resulted in the end of 2021 and much of 2022 being more hectic for international racing than usual.
The World Championships is set to run over six days from 16-21 December, with the European equivalent also running over six days from 2-7 November.
Ireland's youthful European Championships team features three athletes – Eoin Corby, Molly Mayne and Grace Hodgins - that will focus on gathering experience.
The 12 athletes for the Worlds are eight Olympians, including Tokyo 2020 Olympic finalist Mona McSharry.
The Irish team for the World Championships will also feature Olympic Top-16 finisher Daniel Wiffen and Shane Ryan and Danielle Hill, who have performed notably in the 2021 season of the International Swimming League (ISL).
Fellow Olympians Brendan Hyland, Finn McGeever, Jack McMillan, and Ellen Walshe will also compete, with Darragh Greene the only Tokyo 2020 swimmer not travelling, as he only recently returned to the training pool after an extended post-Olympics break.
Identified relays will once again be a strong focus for the Irish contingent with some athletes selected to the team specifically for this purpose.
National Performance Director Jon Rudd said: "After what was our most successful Olympic Games in at least 25 years, we are delighted to be able to return to some high quality international racing, something that eluded us during 2020 and 2021 as we approached Tokyo.
"There’s very much an eye on the future with some of these athletes and they all met what we felt was a stringent and robust Selection Policy to make these teams.
"Some athletes have been unable to take up their places, particularly for Kazan, as November is not an easy period for those in full-time education, but for those who can take the opportunity, we will look forward to some fast and exciting short course racing across the two meets."
The Swim Ireland Selection Policy permitted Mona McSharry a place on both Irish teams at these two events, but McSharry will focus on the Abu Dhabi event due to her academic commitments.
The athletes returning from Kazan will also race in the 2021 Irish National Short Course Championships, which take place at the National Aquatic Centre in Dublin from the 16-18 December.