- Sligo RFC is one of the oldest clubs in Ireland, having been founded in 1890.
- The Father of the Club was George Hamlet, who was Club President from 1969-1972 and after whom the Hamlet Room in the Clubhouse is named. George was a son of the late George T. Hamlet (Old Wesley), who was capped 30 times for Ireland, and captained the International team on 8 occasions, and who served as President of the IRFU in 1926/27.
George passed away in 2011 having surpassed his 90th birthday.
- Sligo RFC was also honoured when Joe Burgess, who was Club President in 1994/95, was elected President of the Connacht Branch in 2001/02.
- The club had the honour in 1896, of playing in the first Connacht Senior Cup game ever held in the province, when their opponents were University College Galway.
- Sligo won the Connacht Senior Cup for the only time in 1914, defeating Galway Town by 9-3, and they unsuccessfully contested three consecutive Senior Cup finals, against UCG in 1923, 1924, and 1925.
- Between 1925-1974, Sligo played as a Junior side, and enjoyed considerable success. They won the Connacht Junior Cup in 1925 for the first time, and subsequently were victorious in 1954, 1966 and 1968.
- Sligo also won the Connacht Junior League in the 1965/66, 1967/68 and 1971/72 seasons.
- The club was granted senior status by the Connacht Branch in the 1975/76 season, and until 1997/98, competed as a senior club.
- Sligo played in the All-Ireland from 1993/94 until 1997/98, before being relegated after a play-off with Midleton.
- Having returned to junior ranks, Sligo won the Connacht Junior Cup in 1999 and 2005.
- In 2005 also, the club won the All-Ireland U-18 League for the first time, when they defeated Barnhall in a thrilling final in Naas.
- The club regained its senior status in 2011 following a superb Connacht League and Cup double winning season.
- The club also had its best ever run in the All Ireland Junior Cup that season before a last minute drop goal from eventual champions Crosshaven RFC ended Sligo’s run at the semi final stage.
- The club currently compete in Division 2C of the Ulster Bank League.
-Sligo RFC has a thriving underage section.
- Club members, Gavin Foley (1993, 1994), Billy Leahy (2000), David McGowan (2002, 2003), Jason East (2007) and Aaron Spring (2008) were capped for Ireland at Youth Level, while David was also capped for Ireland U-19’s in 2004, and at U-21 in 2005 and in 2006.
In 2014 Conan O’Donnell was capped for the Irish Schools and Matthew Cosgrove picked was capped on the Irish youths.
- 2015 saw Darragh Cummins capped on the Irish Youths while Cillian Gallagher was selected on the Irish schools squad. That year O’Donnell earned more representative honours with the Irish U-20s.
- In 2016 O’Donnell retained his place in the U20 squad for the six nations and was joined in the squad by Gallagher and Stephen Kerins. Kerins and Gallagher played in the 2016 U-20 world championship and were joined in the squad by Cosgrove. O’Donnell also earned a number of senior caps for Connacht over the 2105/16 season.
- The current Sligo RFC crest was updated in 2007 with the re-addition of the escallop shell which in the past was typically attached the the hare’s foot and is synonymous with Sligo (Shelly Place, as gaeilge).
The original crest though was inspired by the Springboks crest from the late forties, and designed by Jack Regan.