Republic of Ireland Premier Division

Organised league football in the south of Ireland dates to the foundation of the League of Ireland in 1921, following a split from the Belfast-based Irish Football Association (IFA). For over six decades the League of Ireland operated as a single-division competition. By the early 1980s, concerns about standards, fixture congestion, and a lack of competitive balance led the FAI and the clubs to explore the creation of a two-tier national structure.

In 1985 the League of Ireland was reorganised into a 12-team Premier Division and a 10-team First Division. The Premier Division became the national top tier, with promotion and relegation between the two divisions introduced from the outset. Derry City, who were based in Northern Ireland and had been admitted to the First Division in 1985, subsequently gained promotion to the Premier Division in 1987, giving the new league a cross-border dimension with the support of FIFA and the IFA.

The inaugural Premier Division in 1985–86 was made up of the top 12 teams from the 1984–85 League of Ireland and included the League of Ireland's traditional powers – Shamrock Rovers, Shelbourne, Bohemians and Dundalk. Shamrock Rovers, who had already won the final two championships of the old League of Ireland era, claimed the first two Premier Division titles and completed a record run of four consecutive league championships from 1983–84 to 1986–87.

Dundalk were champions in 1987–88 and Derry City achieved a treble in 1988–89 by also winning the League of Ireland Cup and the FAI Cup. However, throughout this period attendances and facilities remained uninspiring, European victories were rare, and most clubs continued to operate with part-time squads.

The 1990s saw the re-emergence of St Patrick's Athletic following years of obscurity. They won four league titles between 1989–90 and 1998–99, and became synonymous with attacking, possession-based football under Brian Kerr, Pat Dolan, and Liam Buckley. Cork City claimed their first championship in 1992–93 after a dramatic three-way play-off series with Shelbourne and Bohemians, underlining the increasing geographic spread of the title race.

In the late 1990s and early 2000s Shelbourne and Bohemians became the league's leading clubs. Shelbourne won five titles between 1999–2000 and 2005. They won the 2001–02 title in controversial circumstances, being declared champions after St Patrick's Athletic were deducted 15 points for fielding Charles Livingstone Mbabazi while he was ineligible. Bohemians completed a league and cup double in 2000–01 and added further championships in 2002–03 and 2008.

In May 2001 the League of Ireland clubs voted in favour of switching from an autumn–spring calendar to a summer season running from March to October. The aim of this was to reduce fixture clashes with English football on television, boost attendances as well as commercial and marketing opportunities, improve playing conditions, and encourage better preparation for the teams competing in European competition. The change occurred in the 2003 League of Ireland Premier Division, with the season beginning in March and finishing at the end of October. This eight and a half month season was preceded by a short, concentrated season in 2002–03 from July to January, the first featuring a ten-team Premier Division.

Pat Fenlon, who had been a prominent player for Shelbourne from 1997–2002, had significant success as a manager in the period after the switch to summer football. He won titles with Shelbourne in 2003, 2004 and 2006, before guiding Bohemians to league success in 2008 and 2009. Cork City denied Shelbourne a third league title in a row when they claimed their second title in 2005, defeating fellow challengers Derry City in a final-game decider at Turners Cross.

Financial instability became a recurring theme during the second half of the decade. Shamrock Rovers entered examinership in 2005 after it was revealed that the club had debts of nearly €3 million. It was also discovered that Rovers were not paying PAYE and PRSI taxes. As a result of these financial irregularities, they were deducted eight points, ultimately resulting in the club being relegated to the First Division after they lost the relegation/promotion playoff to Dublin City. This was the first time Rovers' senior team had dropped out of the top level of the Republic of Ireland football league system since the club had joined the League of Ireland in 1922–23.

During the 2006 season the Revenue Commissioners took High Court action and threatened to have Shelbourne wound up after the club failed to pay more than €104,000 in outstanding taxes. Shelbourne also struggled to pay their players during the season. Despite winning the title, Shelbourne were subsequently demoted to the First Division due to their financial difficulties. Midway through the season Dublin City also went out of business and withdrew from the league, unable to complete the season.

During the 2008 season both Cork City and Drogheda United were deducted ten points after going into administration.

Following the conclusion of the 2009 season both Derry City and Cork City were expelled from the League of Ireland. Derry City were accused of making extra payments to players using unofficial secondary contracts. This was against league rules which placed limits on the amount clubs could spend on players' wages. Cork City had been in serious financial difficulties for several seasons and its holding company was eventually wound up by the High Court. However, both clubs were effectively reformed and subsequently allowed to join the 2010 First Division. These crises prompted reforms to licensing and financial regulation within the league.

The early 2010s opened with Shamrock Rovers winning back-to-back titles in 2010 and 2011 under Michael O'Neill. In 2011 Rovers also became the first team in League of Ireland history to qualify for the group stages of the UEFA Europa League. In 2012, Sligo Rovers won their first Premier Division title and their first top level title in thirty five years. St. Patrick's Athletic won their fifth Premier Division in 2013.

From 2014 the balance of power shifted decisively to Dundalk. Under Stephen Kenny, Dundalk won four titles in five seasons between 2014 and 2018. They were renowned for playing an attractive possession-based style, scoring the most Irish top-flight league goals in history in 2015 with 78, and setting a Premier Division record of 87 points in 2018.

In 2016 Dundalk emulated Shamrock Rovers by reaching the Europa League group stage. A draw away to AZ Alkmaar in their opening game saw them gain the first point for an Irish club in the Europa League group stage, and they followed this up with a win over Maccabi Tel-Aviv, becoming the first Irish team to earn a European group stage victory.

Cork City emerged as Dundalk's main rival, finishing runners-up three years in succession before winning the league and cup double in 2017.

In contrast, three Premier Division clubs – Sporting Fingal, Galway United and Monaghan United – all withdrew from the League of Ireland due to financial difficulties. Sporting Fingal subsequently went out of business completely.

Shamrock Rovers re-established themselves as the league's dominant club in the 2020s. Under Stephen Bradley they won four consecutive titles from 2020 to 2023, matching their own national record for successive championships and extending their all-time tally of top-flight titles to 21.

Rovers were also successful in navigating the qualifying rounds of UEFA club competition on numerous occasions. They appeared in the group phase of the 2022–23 UEFA Europa Conference League, the league phase of the 2024–25 UEFA Conference League, and the league phase of the 2025–26 UEFA Conference League. In their 2024–25 UEFA Conference League campaign, they became the first Irish side to qualify for the knockout stages of European competition.

The 2024 title race was widely regarded as one of the most exciting in League of Ireland history, concluding with Shelbourne ending Rovers' run by winning their first title in 18 years under former Republic of Ireland winger Damien Duff. At the other end of the table Dundalk were relegated after 16 consecutive seasons in the top flight. Shamrock Rovers responded to Shelbourne's victory in 2024 by reclaiming the championship in 2025, their fifth title in six seasons.

Throughout this period the league experienced a sharp rise in attendances and profile off the pitch. A 2023 UEFA report placed the Premier Division 28th among 54 European top flights by aggregate crowd and highlighted a 20% year-on-year increase in attendances, while an FAI-commissioned study by BDO estimated the overall value of the League of Ireland to the Irish economy at €164.7million per year. In 2024 the League of Ireland reported that attendances across its three national divisions passed 500,000 by the mid-season break for the first time.

The 2025 season marked the first time that every club in the Premier Division operated on a full-time professional basis, a status change viewed as essential for competing more successfully in UEFA competitions and retaining talented young players for longer. A league match between Bohemians and Shamrock Rovers which was held at the Aviva Stadium in February 2025 set an all-time League of Ireland attendance record with 33,208 spectators.