Southend United played 169 league seasons and cup tournaments in the data, 1910 to 2026. Success weighs every finish by how hard that competition was to win; Efficiency is the share of what the club could have won that it did win; Edge compares that with an average participant (×1.00).
| 806 | Mansfield Town (England) | 2.4 |
| 807 | SG Wattenscheid 09 (Germany) | 2.4 |
| 808 | Cultural Leonesa (Spain) | 2.4 |
| 809 | Southend United (England) | 2.4 |
| 810 | 1.FC Heidenheim (Germany) | 2.4 |
| 811 | FC Amsterdam (Netherlands) | 2.4 |
| 812 | Democrata (Brazil) | 2.4 |