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.