County Armagh woman Sarah Jane Johnston was Ireland's first medal winner as the 2015 Special Olympics World Summer Games got under way in Los Angeles.
The 35-year-old Lurgan woman was one of three Irish swimming medallists on Sunday as she picked up a 100 metres backstroke bronze.
Cork man Sean Coleman and Dubliner Gary McEnroe later clinched 25m backstroke silver and bronze medals.
The aquatic events are taking place at the University of Southern California.
Johnston competes for the Ripples Special Olympics Club in Portadown while Coleman, 22, hails from Youghal with McEnroe a native of Tallaght in Dublin.
The county Armagh woman is one of 12 Ulster athletes in the 88-strong Ireland team competing in Los Angeles until next Sunday.
Lisburn lad Christopher Kane, 19, is representing Ireland in five-a-side football along with Ballynahinch 20-year-old Peter Fitzpatrick with Newtownabbey woman Carole Catling, 37, aiming for table tennis success.
Belfast woman Kirsty Devlin, 20, will participate in the gymnastics arena along with Letterkenny man Patrick Quinlivan, 32, while another Donegal native Oliver Doherty, 38, will be aiming for golf medals along with Scarva woman Jill Connery, 29, and her playing partner Belfast lady Ursula McDonnell, 71.
The other Ulster hopefuls are 14-year-old county Armagh equestrian competitor Dearbhail Savage plus Coleraine ten-pin bowler Sean Campbell, 30, and Strabane kayak contender Nuala Browne, 38.
The Games officially got underway at a star-studded opening ceremony at the Los Angeles Memorial Coliseum, site of the 1932 and 1984 Olympics Games.
First Lady Michelle Obama gave an impassioned speech about the importance of the global Special Olympics programme and the benefits it offers to athletes with intellectual disabilities.
Special Olympics Ulster's regional director Shaun Cassidy said that he was "thrilled" with Ireland's success on the first day of competition.
"Our congratulations go to all of the athletes and particularly Ulster's Sarah Jane Johnston who recorded the first medal win for the team," said the Special Olympics Ulster official.
"The excitement from Team Ireland volunteers, families and supporters is being felt at home and abroad, with a great buzz building on social media and we invite everyone to join us in cheering on our Team Ireland athletes on as LA2015 continues."