Of the three regional leagues whose champions qualify for promotion to the Nationwide Conference (formally Conference League), the Isthmian was once the most dedicated to amateurism...their champions did not even have a trophy, the League policy being that the honor sufficed. Teams less able to compete financially thus gravitated to it rather than the Dr Martens Southern League, while those with ambition and money would move in the opposite direction.
With the regularization of promotion to higher leagues for champions, repeat champions of this league have become a thing of the past...however, Canvey Island F.C. have been runners-up in the 2000/2001(to Farnborough), 2001/2002 (to Gravesend & Northfleet), and 2002/2003 (to Aldershot) seasons, besides winning the FA Trophy in the first of those seasons and getting to the Third Round Proper of the FA Cup in the second.
The league formerly had Premier, First, Second, and Third Divisions, but now has divisions named Premier, One (North), One (South), and Two. They extend from the sixth down to the eighth, no longer to the ninth, tiers of the football pyramid. Teams from Division Two must compete for promotion to the two Division Ones with teams from the Combined Counties League and Essex Senior League. There is a league cup, open to teams of all divisions, sponsored by Bryco.