The season runs from September to April and comprises twenty-two rounds of matches, with each club playing each of its rivals, home and away.

The results of the matches contribute points to the league as follows: Nine of last years teams participate in this season's competition.

Champions, Camborne were promoted to National League 2 West while Old Centralians (11th) and Drybrook (12th) were both relegated to Regional 2 Severn.

The teams coming into this season's competition are Old Redcliffians and Bournemouth, both relegated from National League 2 South in 15th and 16th position respectively.

The season ended before all the matches were completed because of the coronavirus pandemic and the RFU used a best playing record formula to decide the final table.

Initially, Bromsgrove were due to be level transferred from Midlands Premier but the withdrawal of Birmingham & Solihull from the league system meant that they stayed put, leaving South West Premier with just thirteen teams.

They are joined by Barnstaple, who were relegated from National League 2 South, and by three promoted sides; Drybrook, Exeter University and Old Patesians.

The team with the best playing record, in this case Westcliff, hosted the match and beat their opponents Barnstaple 44 – 5 to win promotion to National League 2 South for the first time.

Ten of the fourteen teams participated in last season's competition (when it was known as National League 3 South West).

They are joined by Exmouth, who were relegated from National League 2 South, and by three promoted sides; Weston-super-Mare, Maidenhead and Newbury Blues.

The team with the best playing record, in this case Guernsey, hosted the match and beat their opponents Bournemouth 38 – 23 to win promotion.

They are joined by Launceston who were relegated from National League 2 South, and by two promoted sides: Camborne and Salisbury.

The team with the best playing record, in this case Wimbledon, hosted the match and destroyed their opponents Dings Crusaders 55 – 5 to win promotion.

Bracknell, who finished 3rd last season, transferred to National League 3 London and SE.

[38] After three seasons, in 1996–97, a further reorganisation occurred, and there was a return to four, tier five leagues; with South West Division One covering the area of south-west England from Berkshire westwards.

[39] This system prevailed until 2009–10 when the number of teams was increased from twelve to fourteen and renamed National League Three South West.

The last play-off was in 2018–19, with the next two seasons cancelled due to the COVID-19 pandemic in the United Kingdom and following the increase of leagues at this level to three, only the champions are promoted.