Together with Home Farm, Bray Wanderers, Athlone Town and the reserve teams of Shelbourne, Bohemians, St Patrick's Athletic, Dundalk, Drumcondra and Drogheda, they had been founding members of the B Division in 1964–65.

[10] They took the place vacated after Mervue United and Salthill Devon withdrew from the league to make way for Galway F.C.

[10][11][12] However, after a disappointing season, during which they finished sixth, the club decided it was not financially viable to continue in the league and they subsequently withdrew.

[13][14] An announcement was made in January 2020 that a team using the name Shamrock Rovers II would be entering that seasons League of Ireland First Division.

On 20 February 2021 it was announced that Shamrock Rovers II would not participate in the 2021 League of Ireland First Division, as the Football Association of Ireland opted to replace the team with newly formed Limerick club Treaty United.