It is currently served exclusively by South Western Railway, although historically there were some additional trains operated by Southern.

The original station was opened by the London and South Western Railway on 1 May 1861 and named Portswood after the small village to the west of the main line.

However to avoid confusion with Portsmouth, the station was renamed to St Denys on 1 January 1876.

[1] The station buildings themselves are fine examples of the Victorian Italianate classical style architecture introduced to the LSWR by William Tite.

The original 1867 station building on platform 1 is Grade II listed, now privately owned and renamed Drummond House.