2005–06 National Division One
The 2005–06 National Division One was the 19th full season of rugby union within the second tier of the English league system, currently known as the RFU Championship. New teams to the division included Harlequins who had been relegated from the 2004–05 Zurich Premiership, while Doncaster and Newbury were promoted from the 2004–05 National Division Two. Additional changes saw Penzance & Newyln RFC rebrand themselves as the Cornish Pirates as well as moving from their home ground, the Mennaye Field in Penzance, to a more central location in Truro at the Kenwyn Rugby Ground with the aim to appeal more to Cornish fans on the whole as well as making home games more accessible. Rotherham Titans also rebranded themselves as 'Earth Titans' for sponsorship purposes for this season.
After only one season Harlequins won the National Division One at the first attempt and returned to the Guinness Premiership for season 2006–07. Bedford Blues finished in second place and there was no relegation to National Division Two following the RFU's decision to expand National Division One from 14 to 16 teams for the 2006–07 season.
Participating teams
| Team | Stadium | Capacity | City/Area |
| Bedford Blues | Goldington Road | 5,500 | Bedford, Bedfordshire |
| Cornish Pirates | Kenwyn Rugby Ground | 5,800 | Truro, Cornwall |
| Coventry | Butts Park Arena | 4,000 | Coventry, West Midlands |
| Doncaster | Castle Park | 3,075 | Doncaster, South Yorkshire |
| Earth Titans | Clifton Lane | 2,500 | Rotherham, South Yorkshire |
| Exeter Chiefs | County Ground | 5,750 | Exeter, Devon |
| Harlequins | The Stoop | 12,500 | Twickenham, London |
| London Welsh | Old Deer Park | 4,500 | Richmond, London |
| Newbury | Monk's Lane | 8,000 | Newbury, Berkshire |
| Nottingham | Ireland Avenue | 4,990 | Beeston, Nottinghamshire |
| Otley | Cross Green | 7,000 | Otley, West Yorkshire |
| Pertemps Bees | Sharmans Cross | 3,500 | Solihull, West Midlands |
| Plymouth Albion | The Brickfields | 6,500 | Plymouth, Devon |
| Sedgley Park | Park Lane | 3,000 | Whitefield, Greater Manchester |
Results
Round 1
----Round 2
----Round 3
----Round 4
----Round 5
----Round 6
----Round 7
----Round 8
----Round 9
- Postponed. Game rescheduled to 17 December 2005.
Round 10
----Round 11
----Round 12
----Round 9 (rescheduled game)
----Round 13
----Round 14
- Postponed. Game rescheduled to 4 February 2006.
Round 15
----Round 16
----Round 17
----Round 14 (rescheduled game)
----Round 18
----Round 19
----Round 20
----Round 20 (rescheduled games)
----Round 21
----Round 22
----Round 23
----Round 25 (rescheduled game)
- Game brought forward from 15 April 2006.
Round 24
----Round 25
- Rescheduled. Game brought forward to 8 April 2006.
- Newbury were awarded a 0–0 win and 4 league points following this match. Pertemps Bees won the match by 35 pts to 22 pts but due to a severe injury crisis had to field three unregistered players with the prior approval of FDR in order to fulfil the fixture. All points gained by either side in the match will be disregarded for the purpose of the official league table in accordance with the RFU Regulations.
Leading scorers
- Note that points scorers includes tries as well as conversions, penalties and drop goals.
Season records
Team
;Largest home win — 65 pts70 - 5 Harlequins at home to Exeter Chiefs on 22 October 2005
;Largest away win — 52 pts
68 - 16 Bedford Blues away to Pertemps Bees on 11 March 2006
;Most points scored — 79 pts
79 - 22 Bedford Blues at home to Newbury on 29 April 2006
;Most tries in a match — 12
Harlequins at home to Exeter Chiefs on 22 October 2005
Bedford Blues at home to Newbury on 29 April 2006
;Most conversions in a match — 9
Bedford Blues at home to Newbury on 29 April 2006
;Most penalties in a match — 7
Coventry at home to Newbury on 11 March 2006
;Most drop goals in a match — 2
Plymouth Albion at home to Exeter Chiefs on 3 September 2005
Player
;Most points in a match — 34Alastair Hepher for Bedford Blues at home to Newbury on 29 April 2006
;Most tries in a match — 5
Richard Welding for Cornish Pirates at home to Earth Titans on 18 September 2005
Ugo Monye for Harlequins at home to Exeter Chiefs on 22 October 2005
;Most conversions in a match — 9
Alastair Hepher for Bedford Blues at home to Newbury on 29 April 2006
;Most penalties in a match — 7
James Moore for Coventry at home to Newbury on 11 March 2006
;Most drop goals in a match — 1
N/A - multiple players
Attendances
;Highest — 12,500Harlequins at home to Plymouth Albion on 29 April 2006
;Lowest — 325
Sedgley Park at home to Newbury on 18 February 2006
;Highest Average Attendance — 8,996
Harlequins
;Lowest Average Attendance — 549
Orrell