".....the Irish players were dancing gleefully in a shower of gold descending from their mascots. Flags were waving all over the stadium, the Irish national anthem blared from all sides...." (GF8)
The colour of their robes is green (GF8).
Aidan Lynch (Seeker)
Barry Ryan (Keeper)
A Quidditch match was played in 1385 in Lancashire by an Irish side against an English side, the first mention of Ireland playing Quidditch. The Irish players were run out of town after displaying skills with a Quaffle that had never been seen before (QA8).
The 1994 team won while flying Firebolt racing brooms (PA4, GF8), the same broom that Harry Potter received as a mystery Christmas gift during his third year (PA11). They were favourites to win, but the match ended with a surprise Snitch capture by Bulgarian Seeker Krum (GF8).
A spectacular save that Keeper Barry Ryan had made against the Polish National Team in an international match after the 1994 tournament was the basis for favourable comparison to one of Ron Weasley‘s saves for the Gryffindor Quidditch team (OP19).
The players on the Irish National team that won the Quidditch World Cup in 1994 were all named after friends of J K Rowling (JKR).
Although Ireland won the 1994 World Cup and has a Quidditch team in the British and Irish Quidditch League, there is no mention of Quidditch or any other wizarding sport on their Wikipedia page (Wikipedia).
Lexicon timeline of Quidditch
Lexicon list of World Quidditch teams
From the Web
Writing by J K Rowling on Imgur (Daily Prophet coverage of the 2014 Quidditch World Cup, originally from Pottermore):
Harry Potter Wiki: Irish National Quidditch Team