First level

The League of Ireland was founded in 1921 as a single division known as the A Division. The inaugural season featured eight teams from County Dublin, all of whom had spent the 1920–21 season playing in the Leinster Senior League: Bohemians, Dublin United, Frankfort, Jacobs, Olympia, St James's Gate, Shelbourne and YMCA.^[1][2] Bohemians and Shelbourne had previously played in the 1919–20 Irish League. St James's Gate were the inaugural champions, and also went on to complete a treble, having also won both the FAI Cup and the Leinster Senior Cup.^{[citation needed]}

The League expanded to twelve teams in 1922–23. Among the new members were Shamrock Rovers, who would win the title at the first attempt, and Athlone Town, who became the first team from outside County Dublin to compete in the League. Along with Bohemians and Shelbourne, Shamrock Rovers would go on to dominate the League during the 1920s and 1930s.^{[citation needed]}

Bray Unknowns and Fordsons became the second and third teams from outside County Dublin to join the League in 1924–25, the latter also becoming the first team from Munster to play in the league. The League continued to expand both numerically and geographically during its first two decades, with Dundalk being elected in 1926–27 and subsequently becoming the first team from outside County Dublin to win the title in 1932–33. Dundalk were subsequently joined by Waterford in 1930–31, Cork Bohemians in 1932–33, Sligo Rovers in 1934–35 and Limerick in 1937–38. Sligo Rovers became only the second team from outside County Dublin to win the title in 1936–37.^[1][2]

Cork United emerged as the strongest team in the League during the Emergency, winning five titles between 1940–41 and 1945–46, three of which in succession. However, they subsequently resigned from the League in 1948.^[3]

The 1950s was marked by the emergence of St Patrick's Athletic and the re-emergence of Shamrock Rovers, with the former winning the title at the first attempt in 1951–52 and claiming two more in the middle of the decade, and the latter winning their first title in fifteen years in 1953–54. While Drumcondra and Dundalk won two titles each during the 1960s, Waterford were the dominant team of the decade by winning four titles, including three in succession between 1967–68 and 1969–70. Six different teams won the title during the 1970s, with Bohemians, Dundalk and Waterford each winning two titles. While Athlone Town won two titles at the start of the 1980s, the decade was marked by the four successive titles won by Shamrock Rovers between 1983–84 and 1986–87.

Following the conclusion of the 1984–85 season, the League was restructured and the A Division was replaced by the Premier Division.^[1][2]

Second level

A second division known as the B Division was introduced in 1964–65, featuring reserve teams and emerging senior teams. While there was no formal promotion and relegation to and from the A Division, a number of B Division teams, including Athlone Town, Bray Wanderers, Home Farm, Longford Town, Monaghan United and UCD, were subsequently elected to the A Division.^[4][5]

The B Division was replaced as the second-level division by the First Division in 1985, featuring first teams and promotion and relegation to and from the new Premier Division.^[1][6][7]

Third level

A third division known as the A Championship was introduced in 2008, and like the former B Division featured reserve teams and emerging senior teams. However, unlike the B Division, there was promotion and relegation between the Premier Division, First Division and A Championship.^[8][9]

The A Championship was disbanded following the conclusion of the 2011 season.

Youth leagues

A number of youth leagues have also been introduced since the 2000–01 season.

• The original youth league was an under-21 division, and later became an under-20 division before becoming an under-19 division, the winners of which are awarded the Dr Tony O'Neill Cup.^[10][11]
• An under-17 division was introduced in 2015.^[12][13]
• An under-15 division was introduced with a truncated season in 2017, before fully aligning with the League calendar in 2018.
• An under-13 division was introduced in April 2019.^[14][15][16]

League structure

There are 20 teams in the League, organised into two divisions: the Premier Division (formerly the A Division) and the First Division (formerly the B Division), which were renamed in 1985. There are ten teams in each division, and in a given season each team plays the other nine four times: twice at home and twice away, resulting in a total of 36 games per season.

Teams gain three points for a win, one for a draw, and zero for a loss. At the end of the season, the last-placed team in the Premier Division is relegated, with the winner of the First Division being promoted in their place. The second- to fourth-placed teams in the First Division compete in a playoff series, the winner of which plays the ninth-placed team in the Premier Division to determine the final place in the Premier Division for the following season.

2023 Premier Division

Cork City

Derry City

Drogheda United

Dublin

Dundalk

Sligo Rovers

Dublin teams
Bohemians
St Patrick's Athletic
Shamrock Rovers
Shelbourne
UCD

Locations of Premier Division teams

Bohemians

St Patrick's Athletic

Shamrock Rovers

Shelbourne

UCD

Locations of Dublin Premier Division teams

2023 First Division

Athlone Town

Bray Wanderers

Cobh Ramblers

Finn Harps

Galway United

Kerry

Longford Town

Treaty United

Waterford

Wexford

Locations of the First Division teams

Former League of Ireland clubs

Apart from the current twenty members, at least 38 other clubs have competed in the League of Ireland at one time or another. Some of these clubs are still active, playing in intermediate and junior leagues. The list below only includes teams that played in the A Division, the Premier Division and the First Division.

First level

By number of titles

By team

By county

More information County, Titles ...

County	Titles	Most successful club
Dublin	60	Shamrock Rovers (21)
Louth	15	Dundalk (14)
Cork	12	Cork United (5)
Waterford	6	Waterford (6)
Sligo	3	Sligo Rovers (3)
Derry	2	Derry City (2)
Limerick	2	Limerick (2)
Westmeath	2	Athlone Town (2)

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By season

For each season, the number of teams competing (in brackets) are shown.

UEFA Champions League

More information Season, Club ...

Season	Club	Round	Opponent	Home	Away	Agg
2009–10	Bohemians	2QR	Red Bull Salzburg	0–1	1–1	1–2
2010–11	Bohemians	2QR	The New Saints	1–0	0–4	1–4
2011–12	Shamrock Rovers	2QR	FC Flora Tallinn	1–0	0–0	1–0
		3QR	F.C. Copenhagen	0–1	0–2	0–3
2012–13	Shamrock Rovers	2QR	FK Ekranas	0–0	1–2	1–2
2013–14	Sligo Rovers	2QR	Molde FK	0–1	0–2	0–3
2014–15	St Patrick's Athletic	2QR	Legia Warsaw	0–5	1–1	1–6
2015–16	Dundalk	2QR	BATE Borisov	0–0	1–2	1–2
2016–17	Dundalk	2QR	FH	1–1	2–2	3–3 (a)
		3QR	BATE Borisov	3–0	0–1	3–1
		PO	Legia Warsaw	0–2	1–1	1–3
2017–18	Dundalk	2QR	Rosenborg BK	1–1	1–2	2–3 (aet)
2018–19	Cork City	1QR	Legia Warsaw	0–1	0–3	0–4
2019–20	Dundalk	1QR	Riga FC	0–0	0–0	0–0 (5–4 p.)
		2QR	Qarabag	1–1	0–3	1–4
2020–21	Dundalk	1QR	NK Celje	0–3[lower-alpha 1]		0–3
2021–22	Shamrock Rovers	1QR	Slovan Bratislava	2–1	0–2	2–3

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1QR/2QR/3QR = First/Second/Third qualifying round; PO = Playoff

UEFA Europa League

More information Season, Club ...

Season	Club	Round	Opponent	Home	Away	Agg
2009–10	Sligo Rovers	1QR	Vllaznia Shkodër	1–2	1–1	1–3
	Derry City	2QR	Skonto	1–0	1–1	2–1
		3QR	CSKA Sofia	1–1	0–1	1–2
	St Patrick's Athletic	2QR	Valletta	1–1	1–0	2–1
		3QR	Krylia Sovetov	1–0	2–3	3–3 (a)
		PO	Steaua București	1–2	0–3	1–5
2010–11	Dundalk	1QR	Grevenmacher	2–1	3–3	5–4
		2QR	Levski Sofia	0–2	0–6	0–8
	Sporting Fingal	2QR	Marítimo	2–3	2–3	4–6
	Shamrock Rovers	2QR	Bnei Yehuda	1–1	1–0	2–1
		3QR	Juventus	0–2	0–1	0–3
2011–12	St Patrick's Athletic	1QR	ÍBV	2–0	0–1	2–1
		2QR	Shakhter Karagandy	2–0	1–2	3–2
		3QR	Karpaty Lviv	1–3	0–2	1–5
	Bohemians	2QR	Olimpija Ljubljana	1–1	0–2	1–3
	Sligo Rovers	3QR	Vorskla Poltava	0–2	0–0	0–2
	Shamrock Rovers	PO	Partizan	1–1	2–1	3–2 (aet)
		Group A	Rubin Kazan	0–3	1–4	4th
			Tottenham Hotspur	0–4	1–3
			P.A.O.K.	1–3	1–2
2012–13	Bohemians	1QR	Þór Akureyri	0–0	1–5	1–5
	St Patrick's Athletic	1QR	ÍBV	1–0	1–2	2–2 (a) (aet)
		2QR	Široki Brijeg	2–1	1–1	3–2 (aet)
		3QR	Hannover 96	0–3	0–2	0–5
	Sligo Rovers	2QR	Spartak Trnava	1–1	1–3	2–4
2013–14	Drogheda United	1QR	Malmö FF	0–0	0–2	0–2
	St Patrick's Athletic	1QR	Žalgiris Vilnius	1–2	2–2	3–4
	Derry City	2QR	Trabzonspor	0–3	2–4	2–7
2014–15	Dundalk	1QR	Jeunesse Esch	3–1	2–0	5–1
		2QR	Hajduk Split	0–2	2–1	2–3
	Derry City	1QR	Aberystwyth Town	4–0	5–0	9–0
		2QR	Shakhtyor Soligorsk	0–1	1–5	1–6
	Sligo Rovers	1QR	Banga Gargždai	4–0	0–0	4–0
		2QR	Rosenborg BK	1–3	2–1	3–4
2015–16	UCD	1QR	F91 Dudelange	1–0	1–2	2–2 (a)
		2QR	Slovan Bratislava	1–5	0–1	1–6
	Cork City	1QR	KR	1–1	1–2	2–3 (aet)
	St Patrick's Athletic	1QR	Skonto	0–2	1–2	1–4
	Shamrock Rovers	1QR	Progrès Niederkorn	3–0	0–0	3–0
		2QR	Odds BK	0–2	1–2	1–4
2016–17	Cork City	1QR	Linfield	1–1	1–0	2–1
		2QR	BK Häcken	1–0	1–1	2–1
		3QR	Genk	1–2	0–1	1–3
	Shamrock Rovers	1QR	RoPS	0–2	1–1	1–3
	St Patrick's Athletic	1QR	Jeunesse Esch	1–0	1–2	2–2 (a)
		2QR	Dinamo Minsk	0–1	1–1	1–2
	Dundalk	Group D	AZ	0–1	1–1	4th
			Maccabi Tel Aviv	1–0	1–2
			Zenit	1–2	1–2
2017–18	Cork City	1QR	FCI Levadia Tallinn	4–2	2–0	6–2
		2QR	AEK Larnaca	0–1	0–1	0–2
	Derry City	1QR	Midtjylland	1–4	1–6	2–10
	Shamrock Rovers	1QR	Stjarnan	1–0	1–0	2–0
		2QR	Mladá Boleslav	2–3	0–2	2–5
2018–19	Dundalk	1QR	FCI Levadia Tallinn	2–1	1–0	3–1
		2QR	AEK Larnaca	0–0	0–4	0–4
	Shamrock Rovers	1QR	AIK	0–1	1–1	1–2 (aet)
	Derry City	1QR	Dinamo Minsk	0–2	2–1	2–3
	Cork City	3QR	Rosenborg BK	0–2	0–3	0–5
2019–20	Cork City	1QR	Progrès Niederkorn	0–2	2–1	2–3
	Shamrock Rovers	1QR	SK Brann	2–1	2–2	4–3
		2QR	Apollon Limassol	2–1	1–3	3–4 (aet)
	St Patrick's Athletic	1QR	IFK Norrköping	0–2	1–2	1–4
	Dundalk	3QR	Slovan Bratislava	1–3	0–1	1–4
2020–21	Shamrock Rovers	1QR	Ilves	2–2		2–2(12–11 p.)
		2QR	A.C. Milan	0–2		0–2
	Bohemians	1QR	Fehérvár		1–1	1–1(2–4 p.)
	Derry City	1QR	FK Riteriai		2–3	2–3 (aet)
	Dundalk	2QR	Inter Club d'Escaldes		1–0	1–0
		3QR	Sheriff Tiraspol		1–1	1–1(3–5 p.)
		PO	KÍ	3–1		3–1
		Group B	Molde FK	1–2	1–3	4th
			Arsenal	2–4	0–3
			Rapid Wien	1–3	3–4

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1QR/2QR/3QR = First/Second/Third qualifying round; PO = Playoff; Group = Group stage

UEFA Europa Conference League

More information Season, Club ...

Season	Club	Round	Opponent	Home	Away	Agg
2021–22	Bohemians	1QR	Stjarnan	3–0	1–1	4–1
		2QR	F91 Dudelange	1–0	3–0	4–0
		3QR	P.A.O.K.	2–1	0–2	2–3
	Dundalk	1QR	Newtown	4–0	1–0	5–0
		2QR	FCI Levadia Tallinn	2–2	2–1	4–3
		3QR	Vitesse	1–2	2–2	3–4
	Sligo Rovers	1QR	FH	0–1	1–2	1–3
	Shamrock Rovers	3QR	Teuta	1–0	2–0	3–0
		PO	FC Flora Tallinn	0–1	2–4	2–5

Close

1QR/2QR/3QR = First/Second/Third qualifying round; PO = Playoff