The 2012–13 National League 1 was the fourth season of the third tier of the English domestic rugby union competitions since the professionalised format of the second division was introduced.

New teams to the division included Esher who were relegated from the 2011–12 RFU Championship, Loughborough Students who were promoted as champions from the 2011–12 National League 2 North along with Old Albanian (champions) and Richmond (playoffs) who came up from the 2011–12 National League 2 South.

[1][2][3][4][5][6] Ealing Trailfinders finished in first place and, as champions, were promoted to the 2013–14 RFU Championship for next season.

Macclesfield, Sedgley Park and Cambridge were relegated to the fourth tier, the first two named, to the 2013–14 National League 2 North and Cambridge to the 2013–14 National League 2 South.

[7][8][9] [10][11] [14] [15] 104 - 5 Rosslyn Park at home to Cambridge on 12 January 2013 105 - 12 Loughborough Students away to Sedgley Park on 4 May 2013 105 - 12 Loughborough Students away to Sedgley Park on 4 May 2013 Rosslyn Park at home to Cambridge on 12 January 2013 Loughborough Students away to Sedgley Park on 4 May 2013 Loughborough Students away to Sedgley Park on 4 May 2013 Ealing Trailfinders away to Blackheath on 13 October 2012 N/A - multiple teams [16][17][18][19] Stuart Hall for Loughborough Students away to Sedgley Park on 4 May 2013 Hugo Ellis for Rosslyn Park at home to Cambridge on 12 January 2013 Stuart Hall for Loughborough Students away to Sedgley Park on 4 May 2013 Tom Wheatcroft for Ealing Trailfinders away to Blackheath on 13 October 2012 N/A - multiple players [20][21][22][23][24] Richmond at home to Rosslyn Park on 27 October 2012 Sedgley Park at home to Loughborough Students on 4 May 2013 Coventry Sedgley Park [25]