Counties Galway, Sligo, Mayo and Roscommon organized their own qualifying rounds, using either a knock-out or round-robin format.

Ballinasloe Town joined during this time and Galway United reserves who also won two titles in a row after Mervues brace.

Gentex of Athlone also joined for the 1987–88 season but withdrew in spring due to membership not being sanctioned by the Leinster Football Association.

[8] This was followed by further membership increase including Gentex of Athlone rejoining with neighbours St.Peters followed by Straide & Foxford United and Galway Hibernians.

[6][7][9] In April 2013 discussions involving John Delaney and the Football Association of Ireland were held regarding reviving the Connacht Senior League.

Representatives of thirteen clubs were invited to a meeting hosted by the Connacht Football Association at the McWilliam Park Hotel in Claremorris.

[11] However, in June 2013 the Connacht Tribune reported that the plans were shelved due to a lack of sufficient interest from the clubs.

Mervue United defeated Sligo Rovers Reserves in the final of the inaugural League Cup, a pre-season competition featuring two legs per round.

From 1990–91 onwards, the CSL champions or best placed non-reserve team were also invited to play in the League of Ireland Cup.

In 1986–87 the representative team defeated Munster and a Leinster Senior League XI in an Interprovincial series.

On all four occasions they played in a regional group that also included Galway United's first team, Limerick and Newcastle West.

The league also featured three future members of the A Championship – Mervue United, Salthill Devon and Castlebar Celtic.

Throughout its history the CSL suffered regularly from clubs dropping out and only two teams, Salthill Devon and UCG/NUI Galway featured every season.