The regular season started on 4 April and was completed by early November. The format saw the 18 teams split into two groups of nine, divided roughly into southern and northern groups. The two groups used a traditional round-robin format. The two group winners, Shamrock Rovers A and Salthill Devon, then played off in a final. Shamrock Rovers emerged as champions. As the highest placed non-reserve team, Salthill Devon also qualified for a promotion/relegation play-off. However they were subsequently promoted directly to the 2010 First Division after their opponents, Kildare County, withdrew from the League of Ireland before the play-off could be played.[2][3][7][8]
Source: loi.ie Rules for classification: 1) points; 2) goal difference; 3) number of goals scored. Note: Reserve teams are ineligible for promotion. (P) Promoted
Source: loi.ie Rules for classification: 1) points; 2) goal difference; 3) number of goals scored. Note: Reserve teams are ineligible for promotion. (C) Champions