The station was shut after reports of a casualty on the track yesterday (July 31) after 6.40pm.
Emergency services were at the scene and a person was pronounced dead.
The incident is not thought to be suspicious, the British Transport Police has said.
All lines – the Thameslink, South Western Railway and District – were disrupted due to the death.
Services on the Thameslink began to return to normal from around 8.30pm.
The South Western Railway was impacted until quite late into the night.
Severe delays lasted on the District line between Edgware Road and Wimbledon for hours too.
A British Transport Police spokesperson said: “Officers were called to a report of a casualty on the tracks just after 6.40pm yesterday (31 July) at Wimbledon railway station.
“Officers and paramedics attended and sadly a person was pronounced deceased.
“The incident is not thought to be suspicious and a file will be prepared for the coroner.”
If you feel affected by what has happened and wish to find support, you can contact the Samaritans on 116 123 via phone for a confidential chat or email jo@samaritans.org.
