St Denys railway station is located in the City of Southampton and is operated by Southwest trains, who host local services which connect passengers to Southampton Central, Portsmouth, Southampton Airport Parkway, Eastleigh and Salisbury.

A ticket office opens during peak times on Weekdays and Saturdays. When this is not open, passengers can use the touch screen ticket machine located at the station's platform's 2 and 3.

Many trains pass St Denys station, four of which call each hour.