2017–18 South West Peninsula League

Three new clubs joined the league: Reserve sides are not eligible for promotion to Step 5.

Godolphin Atlantic and Stoke Gabriel passed the ground grading requirements with a dispensation that certain works had to be completed by 30 September 2018, or those clubs will face a financial penalty.

[2] Stoke Gabriel subsequently sought voluntary demotion because they announced that their groundworks would not be ready by the deadline.

Their success will depend on finishing in the top three in their respective leagues and other factors including ground facilities.

Clubs finishing in the top two in their leagues have the automatic right to promotion if they pass the ground grading.