Rooney, Lauren Kelly and Dean Clancy will represent Irish boxing at the Games under Irish coach Dmitry Dimitruk.
Boxing begins on October 14 in the Argentinian capital.
Most of the Irish squad leave for Argentina today for the multi-sport event. The boxers depart on October 9.
Irish boxing has won one gold (Ryan Burnett) and silver and bronze (Ciara Ginty and Michael Gallagher) at the last two Youth Olympics in 2010 and 2014.
Current European Elite champion Joe Ward, the only Irish boxer to represent his country at the Youth Olympics (2010) and the Olympics (2016), wished Team Ireland the best of luck in Buenos Aires.
Ireland’s 16-strong squad will compete in 9 sports at the third edition of the Games.
TEAM IRELAND YOUTH OLYMPIC BUENOS AIRES 2018
Athletics
Miriam Daly (400m Hurdles), Sophie Meredith (Long Jump), Miranda Tcheutchoua (Hammer)
Badminton
Nhat Nguyen (Men’s Singles)
Boxing
Dean Clancy (Men’s Flyweight), Lauren Kelly (Middleweight), Dearbhla Rooney (Featherweight)
Diving
Tanya Watson (10m Platform)
Karate
Sean McCarthy Crean (+68kg)
Golf
Lauren Crowley Walsh (Women’s Individual, Mixed Team), David Kitt (Men’s Individual, Mixed Team)
Gymnastics
Emma Slevin (Women’s Artistic Programme)
Swimming
Niamh Coyne (50, 100, 200 breaststroke), Mona McSharry (50, 100, 200 breaststroke, 50 freestyle), Robert Powell (50, 100 freestyle, 50 butterfly)
Tennis
Georgia Drummy (Women’s Singles)
The team departs for Buenos Aires on October 3 with Irish athletes in action on every day of the Games.