Within each group, the teams would play a double round-robin to decide their league position.
The four group winners and the four runners-up contested a first play-off round to decide the two promotion slots.
The decider match for second place was played on 28 May in La Blancherie in Delémont SV Muttenz win after the penalty shoot-out and advance to play-offs.
FC Laufen win 5–1 on aggregate and continue to the finals.
[6] 1st match abandonned after 6' due to rainfall: replay June 29 in Laufen.
Mendrisiostar win 4–2 on aggregate and are promoted to 1980–81 Nationalliga B. FC Laufen remain in the division.