1898–99 Southern Football League

This season saw the expansion of Division One up to 14 teams and creation of Division Two South-West, though it was disbanded at the end of the season after all its clubs left.

Overall Division Two champions being decided in a playoff in which Thames Ironworks defeated Cowes 3-1 at The Den.

Division Two South-West was newly formed and short-lived formation.

At the end of the season the division was liquidated and the League returned to 2-division structure.

[3] Sheppey United and Thames Ironworks drew 1-1, leading to Sheppey remaining in Division One and Thames Ironworks joining them.