The competition consisted of two groups of nine teams, with the top four teams from each group progress to the quarter-finals.[1] The groups for the 2015 season were drawn and are shown below in their respective groups.[6]
^ abThe match between Glamorgan and Hampshire was abandoned due to a dangerous pitch (the match was recorded as a 'no result', but Hampshire were awarded 2 points and Glamorgan were docked 2 points).[8]
^Glamorgan were docked 2 points before the start of season after preparing an unfit pitch in 2014.