| Countries: | Ireland |
| Champions: | Munster |
| Count: | 2 |
| Runnersup: | Edinburgh |
| Matches: | 90 |
| Top Point Scorer: | Felipe Contepomi (Leinster) James Hook (Ospreys) (161 points) |
| Top Try Scorer: | Thom Evans (Glasgow) (9 tries) |
| Website: | www.rabodirectpro12.com |
| Prevseason: | 2007–08 |
| Nextseason: | 2009–10 |
The 2008–09 Celtic League (known as the 2008–09 Magners League for sponsorship reasons) was the eighth Celtic League season and the third with Magners as title sponsor. The season began in September 2008 and ended in May 2009. Ten teams played each other on a home-and-away basis, with teams earning four points for a win, and a bonus point for scoring four or more tries in a match. Losing teams also earned a bonus point if they lost by seven points or less.
The ten competing teams consisted of the four Irish provinces, Munster, Leinster, Connacht and Ulster; two Scottish regions, Edinburgh Rugby and Glasgow Warriors; and four Welsh regions, Cardiff Blues, Newport Gwent Dragons, Ospreys and Scarlets. The Scarlets were originally known as the "Llanelli Scarlets", but renamed themselves at the start of the season, in order to reflect their regional identity.[1]
Munster were crowned champions on 30 April 2009 after the Ospreys beat the Newport Gwent Dragons 27–18 but failed to claim a bonus point.[2]
| Team | Stadium | Capacity | City, Area | |
|---|---|---|---|---|
| Cardiff Blues | Cardiff Arms Park | 12,500 | Cardiff, Wales | |
 Connacht | Galway Sportsgrounds | 5,500 | Galway, Republic of Ireland | |
| Edinburgh | Murrayfield Stadium | 12,464 | Edinburgh, Scotland | |
| Glasgow Warriors | Firhill Stadium | 10,887 | Glasgow, Scotland | |
| Leinster | RDS Arena | 18,500 | Dublin, Republic of Ireland | |
| Munster | Thomond Park Musgrave Park | 26,500 8,300 | Limerick, Republic of Ireland Cork, Republic of Ireland | |
| Newport Gwent Dragons | Rodney Parade | 12,000 | Newport, Wales | |
| Ospreys | Liberty Stadium | 20,500 | Swansea, Wales | |
| Scarlets | Parc y Scarlets Stradey Park | 14,870 10,800 | Llanelli, Wales | |
| Ulster | Ravenhill | 12,800 | Belfast, Northern Ireland |
| Team | Pld | W | D | L | PF | PA | PD | TF | TA | Try bonus | Losing bonus | Pts | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Munster | 18 | 14 | 0 | 4 | 405 | 257 | +148 | 49 | 23 | 6 | 1 | 63 | |
| 2 | Edinburgh | 18 | 11 | 0 | 7 | 416 | 296 | +120 | 40 | 30 | 6 | 5 | 55 | |
| 3 | Leinster | 18 | 11 | 1 | 6 | 401 | 270 | +131 | 38 | 20 | 4 | 2 | 52 | |
| 4 | Ospreys | 18 | 11 | 0 | 7 | 397 | 319 | +78 | 39 | 28 | 3 | 5 | 52 | |
| 5 | Scarlets | 18 | 9 | 0 | 9 | 376 | 395 | −19 | 41 | 46 | 3 | 1 | 40 | |
| 6 | Cardiff Blues | 18 | 8 | 1 | 9 | 322 | 361 | −39 | 31 | 36 | 2 | 2 | 38 | |
| 7 | Glasgow Warriors | 18 | 7 | 0 | 11 | 349 | 375 | −26 | 36 | 41 | 4 | 5 | 37 | |
| 8 | Ulster | 18 | 7 | 0 | 11 | 298 | 331 | −33 | 30 | 33 | 2 | 6 | 36 | |
| 9 | Newport Gwent Dragons | 18 | 7 | 0 | 11 | 305 | 429 | −124 | 26 | 39 | 1 | 4 | 33 | |
| 10 | Connacht | 18 | 4 | 0 | 14 | 224 | 460 | −236 | 20 | 54 | 1 | 3 | 20 | |
| Source: RaboDirect PRO12 | ||||||||||||||
Note: Flags to the left of player names indicate national team as has been defined under IRB eligibility rules, or primary nationality for players who have not yet earned international senior caps. Players may hold one or more non-IRB nationalities.
| Rank | Player | Club | Points[3] | |
|---|---|---|---|---|
| 1 |  Felipe Contepomi | Leinster | 161 | |
| James Hook | Ospreys | |||
| 3 | Chris Paterson | Edinburgh | 159 | |
| 4 | Ian Keatley | Connacht | 124 | |
| 5 | Dan Parks | Glasgow Warriors | 117 |
| Rank | Player | Club | Tries[4] |
|---|---|---|---|
| 1 | Thom Evans | Glasgow Warriors | 9 |
| 2 | Fionn Carr | Connacht | 8 |
| Keith Earls | Munster | ||
| 4 | Ben Cairns | Edinburgh | 7 |
| Luke Fitzgerald | Leinster |
Television rights for the league are split between three broadcasters, BBC Wales, S4C and Setanta Sports. BBC Wales and S4C continues to cover the Pro12.[5]