The province plays primarily in blue with white or yellow trim and the team crest features a harp within a rugby ball, the harp being an ancient symbol of the province found in and taken from the flag of Leinster, although the traditional colours of Leinster Rugby mean the design more resembles the flag of the president of Ireland or the coat of arms of Ireland.

Leinster enjoy historical rivalries with all three provincial unions, most notably with Munster, where some games between the teams have been watched by over 80,000 fans in Croke Park.

In addition, Leinster have notable rivalries with two French club teams; erstwhile rivals Toulouse with whom they have jockeyed for the title of Europe's most decorated team, and La Rochelle, a frequent opponent in European competition who defeated Leinster in back to back European Champions Cup finals in 2022 and 2023 under the direction of long-time Munster player Ronan O'Gara.

Although it was not an official touring side organised by the New Zealand Rugby Union, the quality of the match, which was drawn 10 points each, is still remembered to this day.

[7] Leinster's first season in the newly formed Celtic League ended in success as the Lions were crowned the inaugural champions, beating rivals Munster Rugby in the 2001–02 final.

The 2003–04 season also ended in disappointment as Leinster slumped to their worst ever league performance and failed to qualify from their European Cup group.

[9] Leinster also won all of their pool games in that year's European Cup, and were again among the favourites for the title, however they went out at the quarter final stage to Leicester Tigers.

In 2005–06, Leinster progressed to the semi-final but were eliminated by Irish rivals Munster at Lansdowne Road and they reached the quarter-final the following year where they were beaten by eventual winners London Wasps.

Increasing attendances at Leinster games led to a move across Dublin 4 from Donnybrook Stadium to the redeveloped RDS Arena.

In 2007–08, Leinster failed to qualify from their European Cup pool, but did end the season as Celtic League champions, sealing the title with a 41–8 victory over the Newport Gwent Dragons in front of their home fans at the RDS.

Leinster overcame Munster 25–6 in a semi-final in Dublin's Croke Park that broke the world record attendance for a club rugby union game with a crowd of over 82,200.

Also despite having topped the Pro12 league during the regular season, Leinster lost the first-ever Play-off Final 17–12 on their home ground to the Ospreys.

[15] In the 2010–11 European Cup, Leinster defeated the top English teams (Leicester Tigers, Saracens & Northampton Saints), as well as top French sides, Toulouse (who were the defending European champions), Racing Metro & Clermont Auvergne, (the French Champions).

The club finished in second place during the regular season of the Pro12 and defeated Glasgow Warriors by a score of 17–15 in their semi-final play-off match on 11 May 2013.

[25] On 17 May, Leinster were crowned champions of the European Challenge Cup after defeating Stade Français 34–13 in the final at their home ground, the RDS Arena.

Fortunes in the newly formed Champions Cup were better, with the team reaching the semi-final where they were defeated in extra-time by eventual winners, Toulon.

The following day, the EPCR announced that all other matches involving French and UK teams from the same second round would be postponed to a future date.

The province's current kit (2018/19) is blue with a pattern of spearheads on the jersey which takes inspiration from the people of Laighean (the ancient Irish name for Leinster), while the alternative kit is green with gold features, the colours seen in the Flag of Leinster, with a pattern of geographical cutouts for its 12 counties.

The European kit is 'night navy' with the name of each of the 12 counties visible on the jersey written in the ancient Irish alphabet ogham.

The Leinster jersey also features four stars above the crest, to represent the four European Cup titles won to date.

[44] In July 2014, it was announced by the RDS and Leinster rugby that a design competition was being held to develop the arena into a 25,000 capacity world-class stadium, with work expected to commence on the redevelopment in April 2016.

[45] The selling of naming rights to the arena will be a key component in funding the project, with an initial budget of €20,000,000 being proposed.

In 2010 they first played a home league game against Munster, the first time the stadium sold out,[47] and then against ASM Clermont Auvergne.

[51] The following season Leinster hosted Munster, Bath and Cardiff at the Aviva Stadium and remained unbeaten at the ground until December 2012 when they lost 21–28 to ASM Clermont Auvergne.

A move across Dublin 4 to the RDS Arena for Leinster was needed to accommodate growing crowds, as the 6,000 capacity stadium had become too small.

[52] For this reason, Leinster have signed a long-term lease with the Royal Dublin Society to play home games at the RDS Arena.

[56] The decision to structure the game professionally via the provincial network through centralised player contracts and the subsequent on-field success achieved by Leinster and the other provinces resulted in a significant increase in support within a decade.

[58] A previous attendance record in the Pro12 was also set at Lansdowne Road, for a game between Leinster and Munster which drew a crowd of 30,000.

[62] Leinster's European Cup clash against Munster at Croke Park on 2 May 2009 set a world record attendance at the time for a club rugby union game with a crowd of 82,208.

Props Hookers Locks Back row Scrum-halves Fly-halves Centres Wings Fullbacks Props Hookers Locks Back row Scrum-halves Fly-halves Centres Wings Fullbacks Correct as of 16 February 2025.