Republic of Ireland U19 League

Eircom U21 League

The inaugural season of the U21 division took place in 2000–01 and St Patrick's Athletic finished as the first champions. In 2001–02 Waterford United won the title before Cork City won their first title in 2002–03. City then retained the title in 2003–04. UCD subsequently won three of four remaining titles during the U21 era. As well as featuring the youth teams of contemporary League of Ireland clubs, the division also featured the representative teams of junior leagues such as the Kerry District League, the Mayo Association Football League and the Sligo/Leitrim League. In 2004 Sligo/Leitrim reached the final of the Enda McGuill Cup. In addition to featuring UCD, the division also featured three other university teams – NUI Galway, the University of Limerick and Dublin University. The division was also used by the League of Ireland as an avenue for future members of its senior divisions. Both Salthill Devon and Mervue United began their League of Ireland careers in the U21 division. In 2003 Mervue United were Enda McGuill Cup finalists and in 2006 Salthill Devon became the first club to win the Dr Tony O'Neill Cup without having a team in the senior divisions. In addition to competing for the Dr Tony O'Neill Cup and the Enda McGuill Cup, teams in the U21 division also played in several other competitions including pre-season tournaments in 2006 and 2007 and a futsal league in 2007 which was won by Shamrock Rovers. This latter competition evolved into the FAI Futsal Cup.

Eircom U20 League

In 2008, as part of a restructuring of the League of Ireland that also saw the introduction of the A Championship, the U21 division was relaunched as a U20 division. The new division featured the youth teams of the 22 clubs in the Premier Division and First Division plus four other teams – F.C. Carlow, Kilkenny City, Salthill Devon and Mervue United. Cork City were the first U20 champions in 2008–09 followed by UCD in 2009. In 2010 Andrew Myler guided Shamrock Rovers to their first title.

Airtricity U19 League

During the U19 era Cork City have established themselves as the dominant team, winning the Dr Tony O'Neill Cup four seasons out of five and winning the Enda McGuill Cup on three occasions. In 2016 Cork City also became the first team to represent the division in the UEFA Youth League.