Within each group, the teams would play a double round-robin to decide their positions in the league.
The three groups winners and three runners-up, together with the two best third placed teams, then contested a play-off for the two promotion slots.
Further, ES FC Malley and Stade Lausanne Ouchy had been relegated and were no longer represented in this division.
New clubs in this season were Signal FC Bernex-Confignon and SC Düdingen who had both been promoted after winning their 2.
FC Bulle joined the group after being relegated following the 2004–05 Challenge League season.
They were replaced by FC Kickers Luzern and SV Muttenz who had both been promoted after winning their 2.
Theses teams were replaced by FC Rapperswil-Jona who had been promoted after winning the 2.
Runners-up in this group were UGS, who missed their promotion attempt, being defeated by Servette in this play-off final.
In group 3 champions Tuggen, runners-up Red Star and third placed Herisau all failed in the play-off qualification.